Insulation helps prevent unwanted heat gain in summer and heat loss in winter. This blanket of insulation requires thick insulation in the floor, walls and ceiling. The amount of insulation required depends on your climate, for example, a house in Auckland will not require as much insulation as a house in Dunedin. A house in the Wairarapa, for example, has to strike a happy medium for the frosty winters and searing heat of summer.
Airtightness helps control the heat and cool air entering the building. Eliminating draughts creates a healthier home and means less heating required in winter and cooling in summer. Airtightness can be achieved by sealing all joints in the building envelope and ensuring windows are properly installed. The use of products such as Pro Clima are approved for Passive House for use in New Zealand. A blower door test can tell you just how airtight your building is. Airtight means you can control your climate (this is continued further on).
Window and doors need to be triple glazed, with the option of Low E and filled with Argon gas (depending on the climate, it could be double glazed at the top of the North Island). This means that hot or cool air within the home is not lost through the windows, which have a lower R rating (insulation value) than the walls. There are other more important elements of windows, but these can be explored later. The placement of these windows is important for the climate the house is in and how much solar gain is required, as too much leads to overheating in summer.
Thermal bridges must be eliminated or lessened in a passive house. Thermal bridging is most common in aluminium windows, so thermally broken windows are required, timber or UPVC is the choice here. The edge of a slab foundation and corners of the wall framing all need to be accounted for. Continuous insulation helps prevent thermal bridging.
The final main principle is Heat Recovery Ventilation (HRV)
With an airtight building, airflow must be introduced using mechanical means. Think of an HRV as the lungs of the house. An HRV system takes out the stale air and replaces it with fresh air. So as to not lose all the heat you have created in winter, an HRV system encompasses a heat exchanger. This heats the fresh air to the same temperature as the warm stale air you are expelling so as to not create a temperature drop within the home. (depending on the heat recovery capability of the unit).
Certified Passive Houses are known for their super low energy use, thanks to their super insulation, airtightness, and build quality.
For my own Passive house we will be adding solar panels and rain water harvesting to become more renewable.
What materials to use is a huge factor in sustainable design, as well as the actual design itself.
My belief is that sustainable design should be looked at from a multi-angle approach. As well as considering sustainable materials, the design layout etc, the user is the most important factor. If the user for a home renovation or new build is planning on selling the home within a few years, this does not mean that they don’t need to invest in the sustainable options.
Consideration must be made for the potential new owner on the basis of setting them up with a healthy, well constructed and sustainable home.
Every renovated or new home should be healthy to inhabit, warm in winter and cool in summer, damp and mould free and able to withstand our changing demands, families, environment and climate.
This can be achieved in part by choosing sustainable materials that can help the renovated or newly built home last a lifetime.
Sustainable Design Approach
For sustainable materials consider the products origins, use, life span and end of life disposal.
Some products may not be recyclable at the end of their life and can only be landfilled or burnt, but if they last twice as long as other products, this needs to be considered. Some products may last twice as long as others, but are extracted from an unmonitored questionable source and are therefore unsustainable.
Where did the material come from?
The shortest distance from where the item is to your home (to complete its lifespan) the better.
How is the material extracted? Is it a by-product of other processes? Does it create a useless by-product that can only be disposed of? Is the extraction process environmentally damaging? Does it involve mining? Is it a renewable resource? Does the sourcing of these materials impact any native inhabitants such as native flora and fauna?
Let’s take NZ timber as an example. Trees are fantastic to absorb the carbon humans emit and they are a renewable resource as we replant when we chop down. With Radiata Pine and Douglas-fir grown and processed locally the carbon footprint is low, making this a sustainable choice in NZ.
Things to look at here is if it is FSC certified.
“In order to be given FSC certification, a forest must be managed in an environmentally appropriate, socially beneficial and economically viable manner.” (Source FSC UK website page)
If the material has to sustain a heavy production period which includes machinery, water and electricity to run, the carbon footprint of this material could already be high before its even gone anywhere.
For example; Trees felled on a large plantation require human operated machinery to cut, to strip branches, then to lift onto the trucks. The trucks then travel long distances to get it toward the next phase.
Wool requires raising the animal, herding, shearing, sorting, baling and transport before manufacture can begin.
Man-made materials such as plastics and polystyrene require a very lengthy process.
This is then turning the processed raw material into useable goods. So they need to be trucked/shipped to the manufacturer.
This is where machinery and chemicals can be used to create a final product. Mixing materials to make a composite product can also happen, such as composite decking, wool blend carpets etc. More about this (and why you shouldn’t use it) in another post.
For example; The felled and stripped trees will then be cut into blanks for many different purposes. These are then chemically treated to different levels (if required) to be fit for purpose for a building. Some of the by-products of timber manufacturing and processing are shavings and dust. This is used to create products like chipboard and MDF. A lot of NZ timber is exported. Accoya ships NZ timber to the Netherlands to be treated, to then come back to be sold as non-toxic and very durable timber. (There is a specific, but a lengthy reason for this though)
This phase sees the products transported to the retail store to be sold to consumers. Depending on the retailer, the products will likely need to be delivered to the building or project site.
This phase also includes the construction/installation of the materials. For example; assembling the timber framing for housing, installing carpet or flooring, assembling all the individual products to make a kitchen etc.
There is always excess in this process and a consideration to make is what does the retail store or supplier do with excess materials that aren’t sold? Or, as the consumer, what do you do with the leftovers from your project?
This is where we (the consumer) get to use the product. This could be anything from the insulation in our walls to the flooring beneath our feet. What is very important about this section is: How long is its lifespan?
Since humans found faster and cheaper ways to process and manufacture products, we have developed a throwaway society. This could be where we rip up a perfectly good carpet in a newly bought home simply because we don’t like the colour or feel of it. As they are mostly composite materials, most people are likely to throw this in a skip. Which ends up in a landfill.
Lifespan should be considered from a few perspectives and questions should be asked of each material that will be in use.
Is it versatile? Can it adapt to change of owners, style or primary purpose?
How long is it expected to last? What are the manufacturers guarantees? If it breaks or fails, can I simply repair it?
Is it made from man-made (and therefore mostly landfill-bound) materials? Or is it natural and therefore biodegradable materials? Can it be reused in other ways if it is no longer fit for purpose?
Just as important as the lifespan, is its disposal. Nothing lasts forever, and it will eventually need to be disposed of. The question is then, how does this material have to be disposed of? Can it be recycled?
Old Pink Batts or insulfluff in a houses ceiling does not need to be removed, instead, you can lay new insulation over the top. Its a case of the more the merrier. This will actually increase thermal efficiency when installed correctly. Where this fails is if a now deemed unsafe insulation was originally used.
Old carpet that’s threadbare (think the florally patterned stuff from the ’40s to ’70s) is hard to get rid of. However, people planting trees like to use carpet or old underlay at their base to keep the roots moist. Perhaps donating to a community garden is an option.
Unfortunately, when it comes to renovating older homes, there are lots of materials that have no other option than to be landfilled.
Linoleum, hardboard (used on the walls in wet areas until the early ’80s), fibrous plaster ceilings, old electrical cabling and some plumbing pipework. Materials like these have to be destroyed to be removed from the house, as they don’t come out cleanly. Therefore, they are mostly landfill-bound.
In upcoming posts, we will look at common building materials and the sustainable options for each.
Reason for the examples of timber being used: Timber is one of the most sustainable building materials available. As it is a renewable resource and is a natural and local material. It has many diverse uses and has a good end of life disposal options. Every build in NZ contains some form of timber and sustainable options are easily available here.
In Green Perspective Design Studios practice we like to reuse the materials in renovations where possible. This helps divert waste from landfill and ultimately save money and resources.
This isn’t always easy and sacrifices can be made. Eg: insulating existing exterior walls may involve ripping off old gib to then insulate and replace with new gib. Blown in insulation has not been tested long enough for settling.
Each component of a renovation is looked at in a way that will ultimately extend the buildings life, and therefore its purpose. As well as providing a safer and healthier home, for any and all of its occupants in its revitalised new lifespan.
A red-stained 1967 Cedar clad house was in desperate need of a renovation. The house had been added to over the years with a second storey tacked on to the back in the ’70s and a new master suite type room/bigger lounge in the ’80s.
All these extensions meant for a strangely configured house that was in need of a rehaul and rethink.
This article will look at the living and kitchen space. As this renovation is still underway, and at the moment this space is unfinished, it will show you the progress of what is achievable on a very tight budget. The clients are doing all the work themselves with the help of myself and some borrowed tools.
Existing House Plan (before renovation)
This house had an addition in the late ’80s which gave the main bedroom an ensuite and made the lounge larger. The ensuite is on the outside wall with the bedrooms only window, therefore blocking all natural light into the main bedroom.Unfortunately, the positioning of this ensuite means that, by today’s building code, the bedroom is not legally a bedroom, therefore it could only be listed as a 3 bedroom home for resale. The previous owners got away with this by not having a door on the ensuite, therefore the building code clause (G1 and G2) of outside awareness and natural light, means it is still technically a 4 bedroom home.
Seeing as most people are not that open in their spousal relationships, a door is kind of necessary for privacy.
Initial designs saw us moving the ensuite over and creating a new exterior window for the bedroom and an ensuite door. However, the ensuite is surrounded by 3 load bearing walls. So moving it was too expensive and a hassle.
This pushed the design into the direction it has now taken. By moving the entire bedroom to the front/side of the house, it can now have a window and the ensuite stays where it is.
The design of the bedroom/ensuite will come in a later post as it is being built.
The removal of a load bearing wall dividing the new kitchen and dining space will open the room up and allow the kitchen the room it needs to be functional.
The fireplace will move to the new living area and the bed will take the fires spot in the new bedroom.
New House Plan
The first thing to change for this house is the colour. Stained red, this cedar house looks dated and the cedar is terribly dry and in need of oil.
Unfortunately, you can only go darker than your original stain (unless you want to strip it all off and start again, but not in this budget!)
Left: Before. Right: During the first coat
The staining of the house will be finished when we are not in a summer heatwave. The cedar has not been stained in over 15 years. So it is very thirsty and takes an effort to stain. An oil based stain (rather than water-based) was chosen to rejuvenate the cedar.
The kitchen for this 4 bedroom home was far too small and could only fit one person at a time. Not ideal for a family home. The pantry was small and difficult to get to and there was inadequate room for all the kitchen appliances we have in the 21st century.
The client requested an island bench with the hob top on. So as not to be facing away from the dining space and a much better range of storage with a bigger pantry.
To not only keep costs down, but also to prevent huge amounts of waste going to landfill, most of the existing cabinetry was reused (replacing the countertop and doors). What couldn’t be reused was sold.
BEFORE: Not enough room (Reno had started, so more mess than normal)
BEFORE: The small kitchen and dining area.
DURING: Left – The wall being removed. Right – Looking to the kitchen with the new pantry and the wall removed.
This was a very small pokey space with enough room for a 4 seater table if it was against the wall. Once again, not ideal for the house size.
BEFORE: Left – Looking through the arch to the lounge from dining space. Right – lounge to dining space
In the new layout, a new large sliding door replaces the existing window to provide access to a new front garden. With the large load bearing wall being removed, ease of movement between the dining and kitchen has been created.
Window soon to become a door
The lounge was already a very large room and could easily fit a family gathering in it. However, it had to move to accommodate the new Bedroom location.
With its new location, the TV in the lounge will now suffer from less glare. The lounge is more suited to be an enclosed space.
Load bearing wall being removed. Beam to go into place.
Sustainability and design considerations
During this project, not only was the budget a huge consideration, the sustainability of the renovation, but also the resale value of the property. As this house is not a forever home for the clients, the design needs to account for the future use of the house.
This is a large sustainability aspect for me. You don’t want to sell the house just for the new owners to rip everything out and start again, again!
So making the space more user-friendly for potential future owners is important. Whilst you cannot predict who will be the new owners of a home, you can at least generalise to say that a four bedroom home with a swimming pool will be a family home. As the 2 upstairs bedrooms are isolated, this may suit a family with older children. With these deductions, we can assume that a new owner may have up to 3 children. Therefore, providing more space for a family to dine, lounge and cook is important. If we do not provide for these things, the home may not sell for its full value potential.
There has been no skip used for this renovation. All the timber from the removed walls is being reused in the house. Or for a new hothouse in the garden.
Any Gib that is being removed as whole sheets where possible, to be reused.
The carpet will be reused in the new room layouts.
All the veneer doors are to be painted and reused.
The bathroom involves quite a few different specific areas. Like the shower, the toilet and the sink. This post looks at a more sustainable shower.
The whole room is washing things down the drain. Water treatment plants cannot filter out all the chemicals we wash down the drain. So eventually they can end up in our waterways. So we need to consider just what chemicals and materials we are washing away.
As talked about in our Sustainable Laundry post, the things that go down our drains affect the environment.
New Zealand got rid of microbeads in our body wash and face scrubs, this was the epitome of washing microplastics down the drain. With so many natural alternatives, there is no excuse for missing this bathroom item.
These replacements can slowly be made as your plastic items run out. It is not exactly sustainable to throw away perfectly good to use products before they are finished just to shift to a more zero-waste or sustainable bathroom.
This is one switch my hair had some trouble adjusting to at first. Seeing as it has been dyed at least 3 times a year for 13 years, it is very chemical reliant to look healthy. I am now growing out my hair dye to stop using these chemicals and all the plastic they come in. In saying that, travelling with long hair meant I didn’t use any moose, hairspray or similar as I just couldn’t carry it all. This certainly helped to detox my hair and I use no after shower hair products.
My hair naturally frizzes but it’s very greasy at the roots and dry at the bottom. I don’t cut my hair very often (as I do it myself), so dry ends are just a part of that.
These are typically made by home crafters or even by yourself. They are packed full of natural oils and ingredients and have no sodium lauryl sulfate (the thing that makes the bubbles).
I tried these bar shampoo’s for a few weeks and unfortunately, they didn’t suit me as I have naturally very oily hair.
There is a detox phase for this kind of bar, normally two or so weeks where your scalp and hair adjusts to maintaining its own oils. To prevent the build-up of this kind of bar shampoo on your hair an apple cider vinegar can be used.
The great thing is, if the samples aren’t working for your hair, they are great for your body!
So moving to another option where the shampoo bars are essentially the same as the bottled stuff but have no harsh stripping surfactants (like liquid does) and are waterless, the shampoo block.
Personally, this worked the best for me and are reported to work well for most people. I use Ethique St Clements bar as this is designed for oily hair. The brand is Vegan and uses no Palm Oil too!
There is no transition period for this kind of shampoo, as they are similar enough to the liquid kind.
I now only have to lightly shampoo around the roots, every day in Summer and every second day in Winter. No conditioner needed either! As I am only washing the roots, the natural hair oils help to hold down my frizz as I am not washing them away to just replace them with a heavy conditioner.
There is also the no ‘poo option. Literally, no shampoo. A longer adjustment for your hair and scalp is needed. But if you are able to get your hair to this level, you can wash your hair with just water. There are many resources about this option available on the web.
Conclusion for shampoo
The trick to finding the best shampoo would be asking others for their recommendations, looking at reviews and maybe getting a sample pack to try different types.
The synthetic detergent type of block shampoo may seem expensive upfront, but it replaces 3 bottles of shampoo (in Winter this lasts me 5 months, in Summer about 3) so I only need about 3 blocks a year, and no conditioner. The Cold Pressed bars are even cheaper.
Approx. $66 a year for 3 (Ethique) bars, divided by 12 months is $7.33. I was spending about $12 nearly every month on plastic bottles of shampoo and conditioner that contained palm oil.
Shampoo bars are great for travelling as well. No liquid to spill into all your other things!
You do need to keep them dry so they last longer, so I remove mine from the shower when not in use.
Body wash vs Soap
Body wash is often in a plastic container with a plastic pump. Also, depending on the brand, tests on animals and is full of pretty bad chemicals.
Essentially, body wash uses sodium laureth sulphate and other chemicals to strip oils away from your skin and wash them down the drain.
You then get out of the shower and have to use moisturiser to help your dry skin (which you actually just caused by scrubbing your body). Also, what you use to scrub the body wash over you plays a part.
Something easy enough to replace
A plastic scrubber or pouffe can be easily replaced for a more sustainable option. These pouffes have to end up in a landfill (which may end up in the ocean), as they are not recyclable.
These can be replaced by a soap keeper or a flannel and for those exfoliating showers a jute body scrubber.
Soap saver and Jute Scrubber
Switching to a bar soap is not only much more cost effective ($2 or $3 for bar soap vs $6 to $10 good quality body wash) but plastic free. I personally like the Only Good brand as it is palm oil free and available at supermarkets.
The bar soaps last quite some time in a soap saver, vs it being loose in the shower. I have found mine to last about 6 weeks. As with the shampoo bars, they need to dry out in between uses to last longer, they have a tie so they can drip dry in the shower.
A soap saver means there is no need for any pouffe or flannel. Visit our store to buy your own made by Essenjay Design.
Soap Saver bags
A more natural bathroom
All these bathroom replacements will mean that fewer chemicals are washed down the drain. With less suds from bottled products in the shower as well, there is less soap scum to clean!
We will talk about hot water and cleaning in other posts.
With Summer getting fully in swing, the Kiwi way of spending days and evenings outside begins. Either because it’s breezier and cooler than inside, you’re BBQ’ing, or having a cooling water fight, outside is the place to be in summer.
So how can we enjoy a sustainable outside experience?
One great way to enjoy the outdoors is to grow your own vegetables. Summer is obviously the best season for this, as pretty much everything grows. I am not the possessor of a green thumb, but some things are hard to kill, even for me. As there is more than likely more sunshine than rain in summer (as there should be!) watering often and enough is often the leading cause of death.
To avoid plastic packaging at the supermarket, grow spinach, kale and pick lettuce. Cherry tomatoes are delicious to pick and eat straight from the plant. Rambling tomatoes require no staking, so are easy to grow.
Cucumbers and Courgettes go crazy and need to be frequently harvested.
Vegetables are great if you are renting too. As many things can grow well in raised vegetable beds.
I am in the Wairarapa, so our sunshine hours make it easy to grow many veggies. Tui has a great planting calendar to help guide your decisions.
The tomato plants are thriving!
This is a tricky one. Ideally, a saltwater pool would help rid us of chemicals, but these require a bit of research and would be difficult in a pop-up pool as salt and plastic pools aren’t ideal.
Freshwater would be best, but this needs frequent replacing as algae grow with the higher temperatures. In summertime where there is a low supply of water, this is not possible (nor considerate to all the other people using the same water supply).
A balance of fresh water a little chlorine and a pool vacuum might be a good way to cool off sustainably.
This more comes down to the kind of food to use on your BBQ than the BBQing itself. There have been studies that show that when cooking meat the fat dripping onto the charcoal burns and becomes PAH-infused smoke which then coats the cooking food. This is as well as releasing pollution into the air (and your lungs). Propane (or LPG to us) BBQ’s are safer, but make sure you clean them!
Source sustainable meats meaning organic, free range and preferably local, unless you are vegetarian /vegan… then maybe a BBQ isn’t best for this kind of food.
Now, this is something I can get on board with for a sustainable way. Sometimes a good old hose and a bucket are all that’s needed for some fun (water guns are always plastic and break easily). We had a bit too much fun in Thailand for Songkran, which is the Buddhist new year, which has been adapted into a country-wide water fight in their hottest month.
Back in NZ I still love a good water fight, which for tends to be an all adults battle.
If you are a water balloon fighter, rather than litter your lawn in non-biodegradable latex, you can opt for a reusable crochet water balloon.
Watch this space, we will be selling these soon!
Reusable Water Balloons coming soon to our store!
One serious issue we have in New Zealand is the sun. With no ozone layer, we need more protection than other countries. That old “Slip Slop Slap” campaign comes to mind. I prefer to stay in the shade where possible and avoid the sun at peak hours. But sometimes a simple stroll down the road, outside gardening or being in the pool can cause sunburn. A large hat and long sleeves may be the answer, but sometimes its just too hot for this!
With our countries high rates of melanoma, sunscreen is nothing to be skimped on. This is where being zero waste may not be easy, there are recipes to make your own and herbal brands, but some of these homemade options do not have a high enough SPF to protect us and they may not last in the water.
We don’t spend the summer just in our backyard but at the river, beach or in pretty much any body of water.
This is where our sun protection can actually cause harm to the environment. Even washing off sunscreen down the drain in the shower or sink can inadvertently get into our delicate ecosystem, like with the effects of our laundry room.
Biodegradable sunscreens are the best, as they will naturally protect you, but also break down in the environment.
This is the machine that releases plastics into our waterways and also harmful detergents.
Your washing powder is a simple change. A biodegradable brand is not only better for the waterways, but also for your health, as you wear these clothes against your skin.
Choosing a plastic-free brand will help a transition to a zero waste lifestyle. Personally, I use Eco Store powder, but find it needs warm water to properly dissolve. Instead of fabric softener, I add a few drops of either lemongrass or tea tree essential oils to make the clothes smell fresh.
Microplastics have recently been making the news. One source of these is from our washing machines. The clothing we wear, which we wash, shed particles every wash. There are many different studies on just how much they release, it can be up to 250,000 microfibres from one piece of synthetic clothing every time it is washed.
A microscope image of microfibers released during the washing of polyester textiles. Credit to Swiss Federal Laboratories for Materials Science and Technology
How can you change this?
Wear more natural materials, such as cotton, linen and wool. Yes, these materials can also have environmental problems, so aim for organic versions when possible. This doesn’t mean you need to throw out all your polyester, nylon, acrylic, microfibre and other synthetic clothing (most work uniforms are made from this!) as that would be adding plastic to the landfills. Just be conscious in your future clothing purchases.
Wash less. Yes, those smelling gym clothes definitely need a wash. But perhaps not your winter clothes every day, you’re not exactly sweating in them. Jeans can be folded and placed in a plastic container and put in the freezer overnight. The cold gets rid of unwanted smells.
Water from our washing machines goes into grey water waste. This is essentially all the water flushed down your drains that isn’t from the toilet. This goes to a treatment plant where most of the plastic fibres (about 60 to 90%) are filtered out, times that by how many garments, how many people and how many washes per day, an average town of 100,000 would release the equivalent of 15,000 plastic bags into the environment every day. This ends up in our waterways, which find their way to the ocean, which makes its way into our food chain. New research suggests that 80% of plastic pollution is unseen. As in microplastics, everywhere.
There are many nifty inventions coming out after this awareness of microplastics made the news. The Guppyfriend is a bag used for your synthetic clothing in the washing machine. This gathers most of the shed fibres in the corners or the bag, you then wipe them out and throw in your landfill bin.
If you are in the market to purchase a new washing machine, top loaders are found to release 7 times the amount of the synthetic fibres than a front loader. Also, check their water rating to make sure they are efficient.
Hopefully washing machine manufactures can develop their own filtration systems in the near future too.
Austraila and New Zealand water rating sticker
Reuse your water
Grey water can be reused. Depending on council regulations, you can install a system that takes your grey water waste into a tank and then disperses it over your lawn or reused to flush your toilet. You cannot reuse your kitchen grey water.
The greywater system is not to be used on any edible plants. Rainwater harvesting is much better for this.
Greywater recycling systems need a switch to divert the greywater directly into the drain rather than be reused, this is especially good if you are going to be using a drain for something you do not want on your lawn. There are not only council requirements but also building code requirements for a system such as this.
What this all comes down to is that you should be very mindful of what you put down your drains. Toxic chemicals such as drain cleaner, bleach etc. should not be used in your home, but instead something more natural that you can actually inhale safely and like the microplastics, is not harmful to the environment that this eventually ends up in.
We all see these as little energy suckers and I know in winter they are almost essential.
Drying clothing indoors
Drying your clothing inside on clothing racks has actually proven to pose a health risk. It adds moisture to the air with contributes to a damp home. Which, in Wellington means mould.
Sometimes there is nothing to be done about this, as you need to dry your washing and you have no covered outdoor space.
Consider a drying rack (popular in Europe, why aren’t they popular here?!) that you can use in your laundry, open the windows and shut the laundry door with a draft stopper beneath. They use a pulley system so they can stay up high and out of the way.
It would be possible to make one yourself.
Image courtesy of PullyMaid.
If you are looking at purchasing a new tumble dryer, there are thankfully much better options on the market that use less energy than conventional vented machines.
A Heat Pump tumble dryer is one such thing. This uses up to 50% less electricity than a condenser dryer.
In general, there can be minor changes you can make to your laundry room to make it more sustainable. A more environmentally friendly washing powder, maybe a Guppyfriend bag to stop releasing plastic into our waterways and reconsidering how we dry our clothes.
Major changes should only really happen if you have never owned a washing machine or tumble dryer before, they are broken and can be stripped for parts or repaired and sold, or are simply inefficient for you, but can be passed on to another person who cannot afford new.
I am not an advocate of getting rid of things simply because they are outdated.
I am not affliated with any outward links in this post, I just want to share information and hope people gain insight and knowledge from it.