We are building a new home and are trying to chose the best option for insulation. We live in central South Dakota where the weather goes from one extreme to the other. We have high winds, below zero temps, high humidity and high heat, it is rarely "perfect weather". We do not intend on ever selling our home. It will be a long-term family home. We are willing to spend the extra for the foam if it is indeed an energy saver and is safe for our family and weather conditions. Our home plan is a ranch on a cement basement with 4' below ground on back side and regular depth on front side. We have vaulted ceilings in the living and kitchen areas, 2 x 6 walls. It is approximately a 4000 sq ft home. Any suggestions, please help us to make the right choice.

LanDan,

I live in Minnesota which has a very similar climate to your own, one extreme to the other. This type of climate means that moisture is trying it's darndest to get into your house in the summer and out of your house in the winter. This means that anywhere it can get trapped, it probably will. Vapor barriers help but are never 100% effective - I've never seen one that is 100% vapor tight. For this reason we started using closed cell spray foam on the entire house, and using an air to air heat exchanger. This gives you the homeowner entire control over the air quality and humdity in your house. Back 30 years ago, we could build houses that could breath, so moisture trapping wasn't really an issue (of course efficiency was way down as well). The down side to foam is that it is really expensive, probably going to add about $20,000 to the cost of the home, but in my opinion is a far superior product.

Cellulose is a great alternative to foam. Each has their own perks and both are superior to fiberglass.

Cellulose is a "green" product with about 80% recycled material in it. It will resist fire unlike foam and fiberglass. Both foam and fiberglass will melt and create a hole for the fire to work up through. Cellulose is mold, insect and rodent resistant. Rodent will chew through the fiberglass and foam.

I would do cellulose on your normal wood walls and attic and then do foam on the cement walls, if you plan on insulating them.

thankyou for the advice. We have considered using the rigid spray foam in the wood walls of the main floor, a foam board on the basement and fiberglass or cellulose in the ceiling/attic space. We are putting in an electric heat pump. Is that the same as an air exchanger?

Whatever you do, don't use fiberglass anywhere because it has so many air leaks. Spray cellulose in your attic. It will fill up all the nooks and crannies and have a much tighter air seal.

Consider a hybrid system if cost is a factor. We are doing a lot of these right now with new construction. 1 1/2" of rigid spray foam covered by cellulose. The spray foam makes you house air tight and starts the insulation with up to an R-10 in the first 1.5", the the cellulose adds the sdditional r-value needed.