(Although this was written for homes in cold climates, ceiling insulation is necessary for summer cooling in hot climates, too. It keeps the sun’s heat from penetrating into the living space, keeping the house cool and reducing cooling costs.)
Hot air rises. That principle propels hot air balloons off the ground and over the Rio Grande Gorge here in Taos, NM. Hot air fills the balloon, and it naturally ascends.
That same principle comes into play in your home. You heat your home, and the warmed air goes to the ceiling. If the insulation in your ceiling is minimal or lacking, heat escapes, increasing your energy bills and wasting precious fuel.
I heat with wood and have a ceiling fan. I had noticed over the years during power outages, when the fan was not spinning, the house felt much cooler, even with a hot fire going. I became curious about the insulation in the attic.
A friend and I opened up the access panel and took a look around. Pink fiberglass insulation had been blown in a long time ago, so it was not very thick. I called an insulation company, and when the man came out to look, he said it had an R value of about 19.
The R value of insulation says how well it resists heat transfer. The higher the number, the more resistance it has. There are certain minimums that the building code requires. For ceilings, it is R38.
I had two options, the man said. I could add R19 or R30. I wasn’t sure that what I saw in the attic was R19. It seemed thinner in places, so if I added R19, I might be up to code with R38. I opted for R30 to be on the energy efficient side, for an approximate total of R49.
There is no rule that says you can’t do more than what the building code says. Code is a required minimum. You are free to do more, and that’s what I did. There probably is a cut-off point, though, where what you put in doesn’t contribute anymore to energy loss, but I don’t know what that is.
As expected, the heat is staying in the house. The ceiling fan is not the necessity it was. I still use it, as it does distribute the heat, but without it, the difference is barely noticeable.
Since I heat with wood, energy savings are hard to calculate. Considerations are the wood itself, how often I am home and how stormy or sunny it is (I have sunny south facing windows for daytime heating). These things are different each winter, so there is no norm for comparison.
I can approximate that I am burning approximately two cords less per year at a cost of $150 each. That is a savings of $300 per year. The cost of the R30 insulation was $900, so my payback time is three years. As the cost of wood goes up, and it will, my payback time will be quicker.
The added benefit is my comfort level. The house is much warmer, and I spend less time tending the fire. Human comfort and quality of life are as important as saving energy. They just don’t have a price tag.