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Old 04-17-12, 07:17 AM   #16
MN Renovator
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I don't see the issues with berming being that great considering that the house I live in is undergrade without any issues. It seems that as long as you build it with the same considerations as you would with having that bermed area being a basement, I'm not seeing the issue. I see houses all the time with walkout basements in the back of a house where the front of the house is flush with the ground or maybe a step or two above. That sort of house is effectively bermed. Of course the correct solar exposure is fairly critical. In the case of a house that I know of where the owner discussed energy bills, he says that the summer air conditioning is far higher than the winter heating due to almost all of the glass being on the south.

The more that I reading about passive house building and using glass to assist with heat in the winter, whether it is double pane, triple pane, or has a pile of films(won't name the brand name) the more than I'm leaning to having very little glazing when I build a new house. In the house I'm living now, I have the drapes shut pretty much all the time because the solar exposure is terrible in the winter because the big picture windows are not south facing enough for them to get much sun at all during the winter months. My house has about 4 square feet of southern glass and it's about the only glass that brings in a decent amount of light other than the skylight. The skylight is a nightmare though, when I moved in, it had drywall and sheathing and is directly exposed the attic and had water vapor streaks from shower humidity. In the winter this kind of glass lets out all your heat and in the summer it turns my bathroom into an oven. I have little use for the light considering that if its at night I have a single 430 lumen directional LED that does the job using 8 watts. I'm putting serious consideration into having that skylight removed when this house needs to have its roof replaced. It'll free up space for solar PV panels.

So basically my house is setup so that way in the winter I get little heat from the windows and in the summer my house is baking. I had the idea of installing a removable external sheet of polycarbonate plastic or acrylic and putting Gila film on it to block light in the summer but I found out how expensive those sheets were for the massive size of the picture bay window space(three windows). I think what I'll do instead is buy two patio door screens and fashion those into a removable frame to block light and add privacy. The faux wood blinds by Levolor that the previous owners installed are terrible, don't buy from that company or go with wood blinds, these things suck in the heat and reflect next to nothing. I've hit them with an IR scanner in the summer and had them at 110 degrees in a few spots with an indoor temperature at 74 with the a/c going. They are terrible and will be replaced with honeycomb cell shades in no color other than white.

My goal is to get the a/c heat load down to 1.5 tons, I currently have a 2 ton air conditioner and on a design temp day it will run continuously(as it should) and maintain a few degrees above the set point. On a cooler day I usually operate it so it will run in a single period without shutting it off so I can remove as much humidity as possible to make a higher temperature much more tolerable and its working well. The sun-facing windows with bugscreen over the outside should hopefully reduce the load below 1.5 tons and when I replace my equipment I can confidently ask for a 40k furnace and a 1.5 ton a/c.

The reason why I'm talking about my current house is because I can see all the mistakes of this one to avoid with the next one. It seems that even though I've got limited solar exposure I can manage to get my biggest winter heating bill down to $70($60 when subtracting fixed connection fees) in winter 2010/2011 and under $45 or $35 without fixed connection fees 50 therms Jan 2012 and 180 therms for the past 12 months. These are the highest bills for a house 2200sq ft. Granted I need to disclaim that I don't keep my house at 75 in the winter, I allow it to get as cold as I am comfortable living in, same goes for summer. It's too big for my uses but when I bought it, I was buying a house that fit the neighborhood that I want to live in. Happens to be this is a neighborhood mostly with families and not very many singles or couples so the idea was to buy a house that I could sell later on down the line. A future house would likely be in a college campus area where houses that are built under 1000sq ft for one or two people or maybe 2 people and a kid(I'm talking about the average demands of a family, not what I'd live in with 3 or 4 people). I'm willing to live in a small place even if it were a family of 4 but I won't build for a family of 4 when I'm single.

Back to the topic of glazing, I'm not seeing the advantages as far as cost/benefit goes when going beyond either a really good double pane with the appropriate air gap or triple pane windows with almost all of them on the south side of the house and keeping them sized small and using a fairly substantial amount of cellulose and of course appropriate air sealing. Going completely passive seems to have lost it favor for me after seeing a Duluth, MN project get denied the passivhaus standard because they couldn't make the .6 ach50 but were very close. That house is passive though even though it didn't meet the standard. My goal is to lose the $10.50 connection fee with the natural gas provider or whatever that fee is and having heating costs be under $126 in electricity with a combination of a 9k BTU/hr heat pump and resistance heat for when we get below 0f and that thing can't produce, or in case the heat pump decides to fail. I'm still sticking to my 5k BTU/hr design load goal at -20f. The actual heat design temp where I live is between -12 and -15f depending on where I check but I'm not far from an area north that seems to be -18f. With insulating to a 5k BTU/hr heat load at -20f I'm not seeing much reason to rely on the sun for heating and it seems to be a better plan for me to consider keeping the sun out during the summer. It seems passivhaus designed use an earth tube and a condenser to do the job. Earth tubes are expensive and it seems that more and more of the project I read about are not doing this. Instead of going completely passive, I'll skip some of the more expensive steps and goals of building the status and going with what works on my terms. Things like the ASHRAE ACH for a house are IMHO way too high. I've done the math, if my house was communicating that many air changes, I'd be frozen out of my house for how much heat I'm putting into it but I have a hard time believing that a little breathing, humidity, and human sweat are as terrible as people make them out to be. IMHO controlling humidity to prevent mold is a much bigger concern that any ventilation system in my area will only require much more air conditioning in the summer to pull the humidity back down so the dew point is below 50f to make the basement safe.
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