Finding a house with a passive solar design?

[DougStache]

My wife and I are starting our adventure of buying a house.  I (like many here) value having a house that will not require a ton of energy to keep warm/cool in the winter/summer.  However, we're looking in a cheaper price range and don't expect to see many houses with an intentionally passive solar design.  Instead, I'm hoping to look for homes that incidentally have features that will partially meet this goal.

I thought I had more questions, but these are the main things I'm unsure about:

1) What "incidental" features should we look for in houses to help this?
2) How can I ask about insulation?  What would a meaningful answer entail?

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Where do you live?

[DougStache]

I live in Kentucky.

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Lovely state! Great features for efficiency:

- High efficiency windows (can be remodeled over time if house doesn't have them today)
- North-facing window exposure to minimize summer solar gain
- Mature deciduous trees to shade the house in summer
- Good layout for cross circulation (surprisingly, the deisigns of many houses don't X-V very well)
- Attic fan (or an attic you could remodel) to exhaust summer heat

[StarswirlTheMustached]

My wife and I are starting our adventure of buying a house.  I (like many here) value having a house that will not require a ton of energy to keep warm/cool in the winter/summer.  However, we're looking in a cheaper price range and don't expect to see many houses with an intentionally passive solar design.  Instead, I'm hoping to look for homes that incidentally have features that will partially meet this goal.

I thought I had more questions, but these are the main things I'm unsure about:

1) What "incidental" features should we look for in houses to help this?
2) How can I ask about insulation?  What would a meaningful answer entail?

I can't help with 1), since it sounds like Kentucky needs more cooling than heat, which is the opposite of up here.

2) As for insulation, just come out and ask what's in the walls and how thick when you tour the place. An inspector (you're getting it inspected, right?) ought to be able to make a pretty good guess based on the age and area if the place has not been renovated to add more.

[DougStache]

Lovely state! Great features for efficiency:

- High efficiency windows (can be remodeled over time if house doesn't have them today)
- North-facing window exposure to minimize summer solar gain
- Mature deciduous trees to shade the house in summer
- Good layout for cross circulation (surprisingly, the deisigns of many houses don't X-V very well)
- Attic fan (or an attic you could remodel) to exhaust summer heat

Thanks for the info!  I will add the high efficiency windows and attic fan to our "want to have" list, but will generally plan on adding those later.  Can you explain the north-facing windows?  I had imagined it being best to have south-facing windows which were exposed in the winter to capture heat, and covered in the summer time. 

I hear you on the cross-ventilation right now - my current apartment has tons of windows, but all on the same side of the building so I get zero breeze blowing through.  Right now it's 68 outside and 76 inside with all windows open.

[DougStache]

I can't help with 1), since it sounds like Kentucky needs more cooling than heat, which is the opposite of up here.

2) As for insulation, just come out and ask what's in the walls and how thick when you tour the place. An inspector (you're getting it inspected, right?) ought to be able to make a pretty good guess based on the age and area if the place has not been renovated to add more.

You'd be surprised on the heating.  We definitely experience all four seasons here.  Generally I use more electricity in the winter than in the summer.

I was hoping for a way to compare prior to getting to the inspection phase.  Is the R-value of insulation information that the realtor can get access to?

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We have south-facing, floor-to-ceiling windows in our Minnesota home and they do indeed provide lots of passive winter heating. I wasn't sure if that would be offset by unacceptable heat gain in the summer for you. Mature, deciduous trees would help shade those windows in the summer. (And of course the sun is higher in the summer.)

[Another Reader]

South facing windows are best for passive solar.  They should allow the winter sun to heat some type of thermal mass if possible.  In the summer, a combination of window design, sun blocking shades and deciduous trees are the most common ways to block the summer sun.  Venting and exhausting attic space is important as well. 

You probably have some passive solar design builders there.  One of the nearby universities may have a solar building center as part of an architectural or engineering department.  I would check those out to see what features work best in your climate and look to add those over time.  But start with a well built and well designed house with south facing windows.

[Daleth]

Thanks for the info!  I will add the high efficiency windows and attic fan to our "want to have" list, but will generally plan on adding those later. 

Also look into getting GOOD QUALITY storm windows with low-E glass. That will achieve just about the same energy savings at a fraction of the cost, and a fraction of the hassle too (it's a lot less disruptive to install storm windows than to rip out and replace your existing windows). I'm not talking nasty 1980s silver storm windows that make a house look like it has braces on its teeth--they come in all kinds of colors these days and can look great. But the low-E glass is ESSENTIAL to getting the maximum energy savings. A few brands to consider: Larson Gold series; GW Trapp; Provia.

[Rural]

I'm south of Kentucky in a new passive solar house we designed and built ourselves, and I can definitely second the south-facing, not north-facing windows. Otherwise, there's no point at all. But do be sure you have those deciduous trees or a porch with a roof to shade the windows (the lower sun angle in winter will let some sun come under if it's done right). It's not actually easy to pull off the angle just right even when you design and build the house, but even some passive solar heating helps.

I'm of two minds on the low-e glass, actually. Ours robbed us of a lot of the solar gain we were looking for this past winter. I think overall it's worth it here, but I'm not at all sure it would be in Kentucky.

On the insulation, ask, and ask about the R value. Code calls for R38 in the roof in Kentucky, but anything older than a couple of years will likely have R30. You don't want less than that. Often it's cheap to add in the attic; ask your home inspector about that. Walls are much more difficult.