Before I go down the expensive road of blowing insulation into our walls at home, I’m hoping to follow these weatherization guidelines to pinpoint some cost-effective energy efficiency projects this winter. I’m starting by doing a little research and asking the experts a few questions about how to best protect my family's leaky Colonial from the cruel winds of Cleveland’s winter.

Admittedly, I know from experience that no insulation inside our walls means we have nothing holding back those winds (we're starting from an R-value of zero). I hope to eventually tackle the blow-in insulation, but we need to fatten up the piggy bank first.

I'm already learning that less can produce more (bang for the efficiency buck). Starting with the cold air around the rim joist (that’s where the foundation meets the rest of the house)—a gap allows a constant breeze into the basement. Our home was built in 1920 using ‘balloon’ style construction, which means the studs go straight up from the foundation to the third floor with no interruption. That creates a big chute for air, including warm air from the radiators, to get sucked up to the attic. Once there, warm air quickly escapes through old leaky windows, through an uninsulated attic crawl space and through the gaps where the chimney and sanitary stack ‘penetrate’ the roof. The one saving grace is the new insulation in the roof which we had to replace a couple of years ago .

So, where do I even begin? I know that the greatest heat loss in a home is usually from air leakage. The most cost-effective place to stop it is in the attic. The least cost-effective measure is window replacement.

But my air leaks start in the basement and, combined with the attic and walls, is probably where I should begin sealing off the cold air from pushing in. The former owners of my home stuffed some fiberglass insulation around the perimeter of the basement foundation. That’s not cutting it, though, not by a long shot.

What is the ‘greenest’ insulation option for doing a crawl space and sealing around ‘penetrations’ such as chimney and sanitary stacks in the attic? Is that a DIY job?

I call Matt Berges, a contractor with Sutton Builders and a consultant for Environmental Health Watch Affordable Green Housing Center, and he tells me that a professional insulation contractor could identify where the leaks are and quote me a price for plugging them up. After I describe my home, he gives me some general advice. He would air seal the basement and attic—everywhere—and combine that with insulation.

Berges says that air sealing the rim joist could be a DIY job. “It’s tedious, but it can be done. You need a tape measure and a knife and only two measurements are needed.”

After you measure (twice!) cut the blocks of Styrofoam and fit them into the cavity above the rim joist. You’ll need to spray foam around the perimeter of the block to seal the loose cut. If you want, put the fiberglass batting back in. Plan on spending a couple of hundred dollars on blocks and on a spray foam product like Great Stuff, Berges says. Home Energy Magazine has a good article on DIY air sealing.

What should I do about my attic crawl space? Berges wants to see it before he offers a specific remedy. It’s easy to insulate the knee wall, but, under that wall, the floor right below could have a cavity or duct (not in my case, since we have radiators, none of which can be found in the attic).

“You need to create what’s called a six-sided wall, and to do that you could have insulation between the studs held in place with meticulously applied plastic or some people even use Tyvek. But, without air sealing, you could find the insulation is just a filter for air. You need a thermal boundary and that includes the floor in the crawl space.”

Spray foam is the best as far as performance goes for sealing; it is also the most expensive. If you’re sealing everywhere, consider a contactor-sized box of the Open Cell spray foam.

As for “green-ness” that is debatable, from the standpoint that there is oil in it, but since it saves much more oil (or natural gas) than it uses, it’s a decent trade-off. Berges works with an insulation company that supplements 40% of the oil with green additives.

“A recycled product like cellulous or fiberglass could be considered green from the standpoint that it is recycled, but it does not perform as well," Berges says, "and getting each and every crevice done right is a real challenge. Those products do not air seal. Fiberglass for example, is only as effective as its stated (R value) number if it is installed perfectly, and trapped in a six-sided, air-tight cavity. If the back side of it is exposed, as it is in most crawl spaces, then air travels right through it.

I do not think insulation is a do it yourself job. Or at least that is one I prefer to leave to the insulation contractors.”

Another option would be to look into the BPI home performance with Energy Star program. They offer a rebate for the initial home inspection (which may run upwards of $500), and then offer a rebate to you if you do the improvements that the BPI contractor recommends. You could get up to $1,250 rebate on energy efficiency work..

I’ll continue to update this page as I find out more information and dive into the wonderful world of home insulation and energy efficiency.

Update

Matt sent me this article from Home Energy Magazine which includes a handy chart (scroll down to page 26) which helps prioritize home weatherization projects by effectiveness. The article talks about superinsulating and stopping air leaks, and has pictures of what it should look like.

A few comments from Matt:

1. I’m not sure the project you described in the basement would cost a couple hundred dollars, as it sounded like I said, in your article.

What I said was more in reference to your situation, where you might buy the larger boxes of foam, and do your attic knee walls at the same time. The foam in the basement rim could be a 1 day job for less than 100 (in material).

2. And air sealing existing windows is very cost effective! It is the complete replacement of old windows that has a longer payback, due to the high cost of the job.

Air seal, air seal, air seal. Then make sure you have adequate ventilation in kitchens, baths, and at mechanical appliances. Make it air tight and ventilate it right. Too tight without adequate ventilation does often result in mold and indoor air problems.

Another thing to be aware of is what your wall cavity is made up of, including sheathing and weather barrier, as the lack of these components can be problematic for certain blown in insulations that would absorb moisture through wood siding (for example).