132. Insulation 101: A net-zero builder’s formula for insulating a super energy efficient home

so what he's doing is not only spraying but he's putting a skin on there a vapor skin and it goes tight as a stud tight to the sheathing welcome to green energy futures your guide to the green energy revolution that's already underway David I cheer for green energy futures this week we share with you the very unsexy secret of how super energy efficient Net Zero home builders use insulation to provide half the heat needed for a home stick around and learn more about spray foam rigid foam bat and blow in insulation and how they're used to make the most energy-efficient home money can buy we call it insulation 101 hi I'm Peter Aragon with habitat studio we specialize in energy-efficient houses we built some of the first Net through energy houses here in Edmonton Canada's net zero energy capital I think it's everybody knows the insulation is is necessary to to keep the cold out we're using more insulation because we're trying to keep the total amount of energy down you know greenhouse gas emissions are a direct relationship of using fossil fuels to heat our houses and the higher levels of insulation reduce the emissions from our houses and save us all kinds of money in purchasing the fuel to heat our houses the effectiveness of insulation is gauged through an R value which is a measure of thermal resistance higher r-value means more insulation are 30 for example loses heat twice as fast as our 60 so what our values are we looking for in a super energy efficient home the kind of levels that that we've found to to work through the optimizing that we've done we starting from the top of the house we we would have somewhere around our 80 or 90 in the in the roof the walls would be about our 40 the windows would be about our 8 in the basement frost walls would be somewhere around our 36 to 38 and we'd have about our 16 under the basement slab we're putting in about double what is going into the typical code build house and about four or five times more then would be in a house from the 50s and does that mean rule of thumb that yours you need half the energy or does it work that way it works exactly that way if the r-value of your wall doubles the amount of energy you're losing is cut in half when you picture insulation the first thing that comes to mind is probably the standard fibreglass pink or yellow batt insulation that's the fluffy itchy stuff that comes in bats or rolls in a variety of materials such as fiberglass mineral wool plastic and natural fibres that insulation would be used mainly in walls it'd be the most common type of insulation in most houses including most new houses the fiberglass insulation is the most economical but it it's very it's hard to install perfectly and so there are always a few little gaps around it and these little air currents kind of degrade the the performance of it mineral wool insulation is a little more expensive it's a little denser let higher r-value per bridge and does a little better job of filling all of the gaps that insulation is still used in super energy-efficient Net Zero homes but increasingly Net Zero builders are using blowing insulation in those 12 to 16 inch super energy-efficient walls blowing insulation consists of little bits of cellulose fiberglass or mineral wool which are you guessed it blown into ceilings and walls to fill every little space it's also blown into cavities and we blow it into our exterior walls it does a better job than the bat of filling all the little nooks and crannies and stopping air flow in that wall particularly the cellulose and you know we'll end up with this full one foot thick sweater wrapping around the whole house and you can see the spaces in between the studs would be filled so there's minimum amount of heat transfer through the wood because it compared to insulation wood is actually a conductor of energy Peters last point is very Porton many NetZero home builders use double two-by-four walls that are 12 to 16 inches thick this minimizes wood to wood contact and thermal bridging further reducing heat loss another increasingly common form of insulation is rigid foam insulation this is an example this would be expanded polystyrene it also comes in a extruded version that's got a slightly higher r-value per inch and you can get board installations made of urethane essentially polyisocyanurate and it has the highest r-value per inch we as a lot of foam insulation in our basement of the board type we insulate under the basement floor and in the inner part of the or these outer part of our basement walls with expanded polystyrene it's about our four per inch and this formulation of it is is moisture resistant and is ok to bury in the ground and to be exposed to the moisture that you can sometimes get in in your base of frost walls rigid foam insulation in the floor but sup – foam insulation in the wall and presto no air gaps no thermal bridging and an air tight warm home our last type of game changer insulation is more like something out of science fiction spray foam insulation has really helped builders seal up new super energy-efficient homes fiberglass insulation won't stop airflow it's basically if you think about your furnace filter that's that's kind of not very dense and you know that that'll just clean the air so fiberglass must be used with some other type of air barrier but the the spray foam is an air barrier and insulation in one product we use spray foam when we need a high r-value in a relatively thin space we also use it to some degree for giving us additional air tightness air tightness is a critical part of energy conservation it's just as important as its insulation a house that's highly insulated but still leaky we'll find that the biggest single-component is is air they kick spray foam insulation is perfect for sealing up every little nook and cranny that's hard to seal with regular insulation some modular Net Zero builders are using spray foam in their wall systems to get more insulation per unit area and to really seal up the home and we would also be aiming for an air tightness level of about point six air changes an hour with the blower door test air leakage gets to be very very important a rule of thumb is that Net Zero ready homes will have less than one air exchange per hour once you achieve this and pair it with a new heat recovery air exchange system you will have saved half the energy you need to heat your home this means the furnace can be smaller and in fact it could be an electric air source heat pump furnace that is solar powered that's it for our look at insulation the most important part of the home energy efficiency equation want to know more about insulation or Net Zero homes check out our blog photogallery and podcast at green energy futures dot CA if you like this video please subscribe to our Channel and check out our other videos for green energy features I'm David Dodge insulation is critical to building a super energy efficient home click here to learn more about building a NetZero energy home that's a home that produces as much energy as it consumes you

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