Thoughts on solar efficiency


When we bought our house here in Los Fresnos it wasn’t thefirst time that we looked at manufactured housing — in fact we had looked quite extensively 2 years prior.  I have thought a lot about the issues of insulation and solar control over the years.  It’s no secret that designing a home to control the effects of the sun has gone from art to science.  Overhang, orientation, materials choice, mass — all these details and more make a huge impact on how well a home stays hot or stays cold on it’s own — without the use of energy.  Any house has to have insulation — that’s an obvious — but it’s the things beyond making sure you have good insulation that often makes the difference between comfort and swelter/freezing.

When we returned from our quick trip to Milwaukee I was surprised (in a good way) about how cool the house had stayed in our absence.  The temps were up there all the while we were gone and we returned to a nice cool house having only done one thing to help keep it cool:  leave a bathroom vent fan running.  The ability of the home to slough off heat is impacted by more than just a little circulation and I wanted to comment on that today.

On our first walk-through we noticed several details about this house that really appealed to us.

  • carport on the North side
  • reflective film on the windows
  • hurricane shutters on all the windows not under the carport.

Yesterday the temps were in the mid 80’s and I touched the inside of the window on the South (hottest) side of the house.  It was remarkably cool.  We do not have double or triple glazing.  We do, however have standard aluminum frame windows and storm window — you know, the kind that run in tracks. The two sets of windows are separated by an air gap about 2” wide.

The reflective coating does a lot to keep the house cool by preventing the transmission of heat rays into the house.  But perhaps the most undervalued benefit is what we achieve because of the exterior mounted hurricane shutters.

Because of the size of the shutter leaves (width and distance apart) the sun never shines directly on the window.  The shutter leave above always shades part of the shutter leaf below — meaning that the direct ray is never getting to the glass.  That’s a huge benefit in keeping the inside of the house cooler.

I have noticed that other, newer homes (manufactured and otherwise) are substituting other kinds of shutters. The rolling anti-hurricane shutters are popular for people that can afford them.  They aren’t all as good as the popular French style which is manufactured with an air-gap sort of feature, allowing you to have the shutter down while still having a reasonable amount of air coming through the window opening.

There are other styles, of course. The most common I see on S. Padre Island’s newer condos is the push-out solid shutter. These are easy to use, and I have no idea how effective they are in aiding cooling in Southern climes.

Our shutters can be cranked shut when we leave for the season, or left open when we are around.  Move them twice a year — once to open when we arrive, once to close when we leave.

If you’re thinking about buying a place for half the year I really do encourage you to consider the impact your windows will have on your heating and cooling bill.  They can make a significant difference in how your place feels and in how much it costs you to keep it comfortable.

I doubt that at this point in life we’ll ever have that earth sheltered home.  We’ve been inside of them and I love the lifestyle but I’m past the desire to want to BUILD one myself, and I’m really not in the mood to buy real estate ever again. I’ll just be happy with what we have.

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2 Comments

  1. Are your shutters easily adjusted? Those look nice! We’ve talked about a roll out awning on a couple of our bigger RV windows. If the sun isn’t shining on them, we like the shades up and the outside coming in, but if the sun is beating in, it would be nice to have an awning out.

    Liked by 1 person

    1. Yes they are, Jim. Only a couple pounds of force to turn the knob on the inside. Work better after I lubed them. First time they were a bit touchy but after a lube they are easy enough.

      In Serendipity we struggled with the idea of awnings on the windows. We had a couple of them but rarely pulled them down. The large awning on the side of the coach we used when the winds were favorable — but we didn’t have a wind sensor on ours, and those sensors often don’t activate soon enough — but we did use that more than the ones over the windows.

      The problem with the ones on the coach windows is that they darkened the inside of the RV so much. Peggy likes her LIGHT! (so do I but it was a bigger deal for her)

      The house isn’t as bright inside as we might like. Between reflective film and shutters we keep a lot of light OUT of the house — but it’s also so much hotter here that we are willing to make that sacrifice as a conscious tradeoff.

      Then again, in the coach the A/C was running more of the time (better insulation in the house) and awnings were a bigger deal in terms of heating/cooling efficiency.

      A lot depends too on your individual feelings about heat. Mileage varies with health and past history — I’m still not sure how we’ll deal with a LOT of sustained heat? Only time will tell.

      Liked by 1 person

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