Help Finding Energy-Efficient House?

[workathomedad]

A MMM-level project is far beyond my reach. My DIY level skills are limited to changing light-bulbs and minor light-bulb repair. Not that I'm not against learning, but assuming the above criteria - I'm trying to come up with a basic list of requirements for a pre-existing home to meet.

The main hang-ups with this seem to be that: Not many homes are built with orientation in mind, the only "energy star" homes appear to be brand new homes (which we'd rather avoid), nobody for sale in our area has dream features like solar panels, geothermal, etc. These features would be more a "maybe someday" feature to add on to an existing build.

So far I have:

• South-facing
• Adequate insulation (or we'll have to add this, and factor it into the price).
• Newer or otherwise adequate windows
• No rooms over the garage (we have this now, and it is a horrible energy drain).

My list is pretty limited, are there any additional criteria you'd recommend?

[Another Reader]

The house does not have to south facing.  The majority of the glass should be south facing.  In many cases, a north facing house will have the family room and other rooms that are usually oriented to the back yard on the south side, at the back of the house.  Those rooms generally have the big windows and the patio doors.

Two story houses have less surface area per square foot and in theory should be more energy efficient.  In practice, it is often necessary to use the heat and A/C more because the second floor is more exposed to the air temperature.  Even with zoned spaces, the upstairs may consume a lot more energy and may be difficult to maintain at a comfortable temperature depending on the environment.

[ShoulderThingThatGoesUp]

Size. My older, smaller home is much cheaper to heat than my previous newer, larger one.

[Clean Shaven]

A few years ago, we moved to a different house that I thought was going to mean a huge increase in utility costs - over 1000 Sq ft larger, higher elevation (colder), propane (old house was on natural gas).

It's actually been slightly cheaper. New house has much better insulation and Windows, concrete roof and stucco (instead of Asphalt shingles and hardiboard siding), heat with pellet stove (propane furnaces run only rarely, when it gets very cold). No A/C means no summer increase in electricity (old house had massive western exposure, which cooked the house and meant constant a/c usage, even with solar screens, window tint, and closed blinds); New house has lots of trees for partial shading.

So, I'd focus on quality insulation above all else. If you're shopping to buy a new house, request copies of the old utility bills from the seller.

[workathomedad]

Thanks! I appreciate the feedback.

It looks like insulation is really the #1 thing you can do, and reducing size is a big help. I'm in Michigan so my biggest cost is Natural Gas for heating. Electricity isn't too bad by keeping lights off, etc. Geo-thermal looks pretty interesting because it covers both heating and cooling, and could always be made "Net Zero" later on by the addition of solar panels.

[clarkfan1979]

I live in FL and bought a north facing house. If I purchased a south facing house our AC bill would probably be 50% higher.

[workathomedad]

Do you not have windows on the back of your house?

[velocistar237]

More windows on south than north, e.g., a salt box style house.
Space over windows to add overhangs to shade windows in summer, sized appropriately for latitude.
Simple pitched roof with few or no skylights.
Space for a ton of attic insulation.
Simple, rectangular shape, with long dimension running east/west.
If there are ducts, they should be within the conditioned envelope.

Air sealing is more important than insulation. Features that penetrate ceiling barriers, like can lights, will at least require some particular attention. If you insulate without air sealing, moist air can travel to cold places, and the resulting condensation can cause rot.

If you buy a house with siding that needs to be replaced, you can use it as an opportunity to add external rigid insulation, like foam board.

I live in FL and bought a north facing house. If I purchased a south facing house our AC bill would probably be 50% higher.

True, that doesn't apply so much in Florida, but when you have south-facing windows, you're supposed to have overhangs that shade the windows in summer and let in light in the winter, by taking into account the two different angles.

It's unfortunate that most builders don't know how to build efficiently. See the Green Building Advisor site if you're interested in this stuff.

[Bob W]

If your buying simply ask for copies of energy bills.

If you get serious have a whole house HERS certified energy audit done for about $300.  They will be able to tell you everything to do and give you a cost analysis of the value of each item.  They will use a blow door tester to find all the leaks.  Many utilities subsidize these audits. 

In general look for a home with a heat pump system,  good insulation and little air leakage.   

Be sure to hire one who is not associated with an HVAC or insulation company. 

[workathomedad]

Thank you!

[deborah]

This checklist is quite good (change North for South if you live in the Northern Hemisphere) http://www.greenmoves.com.au/docs/home-checklist.pdf

[nedwin]

Bob touched on this also, but another important aspect to look for is the efficiency of the furnace and/or AC.  An easy way to tell when looking at the home is to look at the furnace exhaust.  For natural gas, propane and probably oil furnaces and boilers plastic exhaust pipes usually indicate an efficiency over 90%, metal exhaust would be below that.  High efficiency furnaces and boilers will also usually have a drain because moisture in the exhaust gases condenses out.  The furnace may also still have the efficiency sticker on it from installation, which makes it even easier to determine.  As for ACs, I don't know what to look for to determine if it is more efficient or not.