Monday, January 3, 2011

Energy Recommendations

Last post I went over the many holes (figurative and literal) in our home's energy use. Obviously there is much room for improvement, both in energy conservation and financial considerations. We're looking for a good balance of both, with an added desire for an increase in our family's day-to-day comfort. And yes, we realize all of this could have been avoided if we'd built a new house, or even bought one built after 1940 when most houses were built with insulated walls standard---but we love this house, so what could we do?

I'll start with a recommendation that I am 100% sure we will not be doing, at least not in the foreseeable future, and that is replacing the original windows with new Energy Star models. Yes, we have air leakage around the pulleys, and yes, they are single pane, but we have exterior storms for the winter and can weather strip/caulk on the inside if need be. Our reasoning to nix the new windows is two fold: 1) we really like the originals and 2) it will cost a ton of money for measly savings. According to our report, laying out tens of thousands of dollars in windows would save us only about $300 a year on our bills and 5% in energy usage. In our opinion, not enough bang for the lotsa bucks.

So what DOES give us the most bang? The winner for cost savings is attic insulation! We would not only reduce our energy use by 23%, but also get back 36% of the project cost in yearly savings. When you combine this with the air sealing (also done in the attic, as well as the basement), we cut our use by an additional 6% and recoup an extra 18% of our project outlay. The project would entail using closed cell spray foam to seal attic leaks and basement rim joists; removing the whole house fan and patching the ceiling; building dry wall boxes around the recessed lights; and insulating the attic door. Additional insulation (R-39) would then be installed with our existing R-11 to bring us up to (actually slightly over) the recommended R-49 for our area. This is definitely on our to-do list.

Now we come to the wall insulation (tops in cutting energy usage, and also helpful in reducing air leakage). This is tricky, as we are not about to gut the place. Brian proposes a dense pack cellulose to be blown into the walls. This can be done from the interior of the house, but drawbacks include holes every 16" in every room/hallway of the house, which then need to be patched and painted. Oh, and there's all the dust and moving furniture around, too. It can also be done from the exterior of the home, which is less messy and disruptive, but this method has its own cons. A row of siding all the way around the house must be removed on each floor; holes are then drilled and patched. The potential problem comes with reinstallation of the siding--ours is aluminum and who knows how old; if it were to crimp, bend,  or be otherwise ruined, we'd have to get new siding to match, which will most likely be darn near impossible and leave us with two discolored bands wrapping around the house, as well as the additional expenses siding replacement would entail.

There is a third option, mentioned by Brian during the audit, which we are hoping works for our home; blowing the insulation into the wall cavities from the attic and basement. The one drawback to this method is that coverage may be less thorough, and we may feel cold spots or experience settling. Our feeling? It's got to be better than nothing, which is what we have now. Insulating the walls could reduce our energy usage by 36% and we'd see a yearly return in savings of 28%.

All of this work is leading up to the big kahuna---putting in some form of a central heating/cooling system. But which kind of system is best for us? I have considered three: a ductless minisplit heat pump; a traditional heat pump, and a geothermal heat pump. With any of these, we'd also be replacing our water heater (15% yearly cost savings, lower energy use by 5%). To be honest, the first one is a non-starter; there is a huge benefit in not needing ducts, but neither C nor I is thrilled with the look of those blowers hanging off the walls ("no better than our window a/c units" says C), and they appear to work better with a more open floor plan anyway. The cost of such a system falls between the other two options, and the energy savings are comparable to a traditional system (16%), but in terms of monetary savings, it's just 4.9% a year of what we'd spend to install it.

Option two is the traditional heat pump. Many of our neighbors have successfully had these installed in their older homes, usually with one unit in the attic and one in the basement, and ducts running up and down through closets. As mentioned above, we'd see a 16% reduction in energy use, but the highest savings; while it chops less off our utility bills than the split system, the initial outlay is smaller so we'd see about 6% back per year. This is probably the most straightforward, practical option.

Option three is geothermal, or using the earth as a heat source/sink. These systems can be extremely efficient, but it is by far the most expensive choice upfront. Our energy usage would be reduced by a whopping 33%, and we'd see almost double the yearly savings as the first two options; however, due to the higher initial costs, this works out to just about 5.5%.  There is also a 30% tax credit for these systems through 2016, as well as other incentives offered by our state, which help defray the costs. I think this is the way we'd like to go, if drilling/excavating our yard is feasible and we can get our home "tight" enough to make it worthwhile.

We will be getting estimates for all of this sealing/insulation work in the coming weeks, and hope to have it complete by the spring, when we can start getting estimates for both traditional and geothermal heat pumps.

I've kept you all long enough--I'll pass on those DIY tips tomorrow, along with a few steps we've already taken that have really helped on the draftiness front!

1 comment:

  1. Really nice read. We have new windows but they were installed without insulation around the frame. Ugh. Refinishing those windows will make them air tight and you can keep the wonderful character.
    Insulating the walls has us rethinking. A few of the Cape Cods near us are just like ours and the walls are open to the basement and attic. Some of the neighbors sealed it up and put in some of the blown in stuff only to find 8 years later, even with a dehumidifier (most of us have sumps in the basement), that the cellulose has compacted and they have some mold.
    Looking forward to your post tomorrow!

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