I want to heat my home with a match.

[Bone1099]

I've heard this term before. You could heat that house with a match. and im pretty sure i know what it means. I'm just not sure how to get there from here. I currently live in a brick home built in 1978ish in NW GA. I heat mostly with a Fisher fireplace insert and my floor plan is not at all intended for the heat to come from where the chimney was built. I want to increase insulation. decrease heat loss and generally tighten up my house it seems to just hemmorage heat. (cash too) I have traditional fiberglass battons in the atic 2 layers. And battons under the floor (oh my god it's a nightmare to work under there) I have replaced all three exterior doors with new containing double pane glass and maybe 1/4 of my windows with double pane glass windows. I want to do some remodeling anyhow so what im really asking is what are the best materials to tighten and insulate my home. Not really thinking of tearing it back to the studs but my main goal is to have a home that i can heat and cool with a minimal effort. Also wanna update to new stove but the boss says bathrooms and living room is higher on list. So when im done with all that and i can buy a new heater i want to need a small one.

 

[woodsman23]

we built a small hunting cabin 16x16 and insulated it well, R60 in the attic, r50 under the floor then covered the floor insulation with peg board for protection from wind and critters and r19 in the 2x6 walls, this place can be heated with a small electric heater on its lowest setting and you still need to open a window,,,,

 

[woodgeek]

The houses you are thinking about are called 'passive houses', and came out of research begun in the 70s energy crisis. You can google all about it: the key is both super insulation AND an almost airtight envelope. The latter requires some sort of forced air system to provide fresh air.

A nice way to benchmark houses is to divide total heat used in a season (in BTUs) by the conditioned square footage and then divide the result by the heating degree days for your climate. Most homes in the US come in around 5-15. 5 houses are very energy efficient, 15 houses are leaky old claptraps. New construction in cold climates runs something like 7. A 'passive house' is nominally 1 BTU/sqft.degday, and use 80% less than the most efficient conventional houses. At that level, they are heated almost entirely by body heat, electrical appliances and solar gain coming in the windows.

IMO, in the 70s, we all learned about insulation and a lot of houses had their insulation upgraded. In many house this did less good than expected, because the houses were not airsealed--the heat goes right around and through the insulation. In the current energy crisis we know better, and just need to fix the airsealing. The good news: airsealing is cheaper than insulation, and DIYable. The bad news: it requires more thought/planning and can be a PITA. Most folks will benefit from professional advice...a blower door test to find the leaks.

I bought a 1960s house that had been upgraded in the 70-80s with storm windows/doors/weatherstripping/extra attic insulation. And it still needed epic amounts of heat. My benchmark score was 11-12...a claptrap. About 40 tubes of silicone caulking later, it is around ~5, a >50% reduction w/o replacing the windows or touching any of the insulation.

some things to do....
step 1: measure how much heat you are using now...start saving elec/propane/gas bills over a heating season.
step 2: read about 'airsealing'.
step 3: if you are using a heat pump, and you think it runs too much, have a tech come and look at it.
step 4: read about insulating brick wall cavities....its a challenge, but even an inch of cavity can be filled to good effect.

 

[semipro]

You've already gotten some good responses. As WG said and Woodsman reported, air sealing and thermal insulation are the key. Unfortunately you can get too airtight but I'd worry about that down the road.

I'd recommend you get a good home energy assessment with a blower door test and thermal IR scan. It will cost you around $300 but the it will be money well spent. The assessor should provide a list of prioritized issues and you'll want to address them pretty much in the order. Sealing the bigger air leaks is a good first step.

Watch out for assessors who are selling something though. If they sell windows you'll probably see those high on the priority list (and unless they're single glazed or leaking badly they probably aren't a high priority).

I'd also recommend you start reading at sites like Fine Homebuilding, The Green building Adviser, Building Science, etc.

Also, look for financial incentives. The feds and sometimes state and local governments may offer rebates, tax credits etc. I was reimbursed 30% of what I spent last year.

Track your energy costs too. Its fun to watch them decrease!

Good luck and have fun with it.

 

[jharkin]

Great info above. Building Science has some very interesting articles to read. There is also a book "Insulate and Weatherise" by Bruce Harley that you should read.

I did the same math that woodgeek did this year. The score for my ooooold house is about a 12. Not bad as a starting point for 200 years old. I did a ton of air sealing and got a subsidized insulation upgrade project done ($3000 value, $600 out of pocket) and Im hoping to get that down a bit. If I can hit a score of 8 I will be very happy. In a house of this vintage doing any better would mean a complete gut and the financial return on investment is just not there.

Which brings me to an important thought. Don't get too hung up on actually achieving some standard like passivehouse. True passive house (where the appliance and occupants provide all heat) as I understand it is pretty much impossible to achieve in a retrofit. Even purpose built its hard - we are talking as air tight as the space shuttle and insane insulation - like R40 in the walls and R60- R100 roofs.

Concentrate on the working from the biggest bang for your buck/time first and then work down. Air sealing, then insulation, and windows/doors LAST.

BTW, Windows I get especially passionate about - so many folks get talked into replacing them first and then you get , maybe, a 5% improvement on your fuel usage for 10s of thousands of $ investment. The same money spent on insulation would give you 10x the payback. The dirty little secret of the window replacement industry is that a $100 storm window gets you 80% of the performance of a $1000 replacement unit. And those replacement windows never last as long as well build old wooden windows (if your house is pre-war). Add some cheap weatherstripping to the original window with that storm and you do even better. And in most houses windows only account for 10-20% of heat loss to start with.

 

[semipro]

Great info above. Building Science has some very interesting articles to read. There is also a book "Insulate and Weatherise" by Bruce Harley that you should read.

I did the same math that woodgeek did this year. The score for my ooooold house is about a 12. Not bad as a starting point for 200 years old. I did a ton of air sealing and got a subsidized insulation upgrade project done ($3000 value, $600 out of pocket) and Im hoping to get that down a bit. If I can hit a score of 8 I will be very happy. In a house of this vintage doing any better would mean a complete gut and the financial return on investment is just not there.

Which brings me to an important thought. Don't get too hung up on actually achieving some standard like passivehouse. True passive house (where the appliance and occupants provide all heat) as I understand it is pretty much impossible to achieve in a retrofit. Even purpose built its hard - we are talking as air tight as the space shuttle and insane insulation - like R40 in the walls and R60- R100 roofs.

Concentrate on the working from the biggest bang for your buck/time first and then work down. Air sealing, then insulation, and windows/doors LAST.

BTW, Windows I get especially passionate about - so many folks get talked into replacing them first and then you get , maybe, a 5% improvement on your fuel usage for 10s of thousands of $ investment. The same money spent on insulation would give you 10x the payback. The dirty little secret of the window replacement industry is that a $100 storm window gets you 80% of the performance of a $1000 replacement unit. And those replacement windows never last as long as well build old wooden windows (if your house is pre-war). Add some cheap weatherstripping to the original window with that storm and you do even better. And in most houses windows only account for 10-20% of heat loss to start with.

Jeremy, I don't know why but when you mentioned "airtight as the space shuttle" I checked out your profile. Sure enough, you're an engineer!

Its just hard for engineers to restrain their true geekyness.

 

[jharkin]

Guilty as charged

 

[begreen]

Personally, I would prefer to build from scratch rather than a complete gutting. Getting an old house's entire house envelope completely tight and efficient is not a trivial task, especially for a full size house. I have friends that gutted their place, inside and out. New windows, sealed all joints. Insulated with fiberglass on interior, and 1" foam board exterior, then tyvek, then reshingled the place. It cost over 100K, but the place is tight and really easy to heat. Solar gain through new Velux skylights often heats the place in mild weather. Their gas bill is trivial now.

OTOH, my BIL built his place from scratch back in the early 80's with staggered 2x4 construction, Pella Windows, foam exterior wrap, tyvek. They heat it with their attached greenhouse a lot of winter days. Maximum fuel usage in NY has been about 2 cords, and often less.

 

[jebatty]

Before I saw this post I was checking websites on btuh/sqft standards. What I found was that 1 btuh/sqft would be regarded as a passive house; 5-15 btuhft would be a very well insulated house, generally new construction; 20 btuh/sqft would be a well insulated house of recent vintage; and 30-50 btuh/sqft is an older home, not well insulated.

What was amazing is that I was seeing current hvac standards for natural gas furnaces still in the 20-30 btuh/sqft class. And I even saw one hvac site touting 50 btuh/sqft as the appropriate standard!

Buyer beware all over again, and do the research if you are in the building or remodeling mode. Energy savings will pay off bigger and bigger as time moves forward.

 

[jharkin]

Personally, I would prefer to build from scratch rather than a complete gutting. Getting an old house's entire house envelope completely tight and efficient is not a trivial task, especially for a full size house. I have friends that gutted their place, inside and out. New windows, sealed all joints. Insulated with fiberglass on interior, and 1" foam board exterior, then tyvek, then reshingled the place. It cost over 100K, but the place is tight and really easy to heat. Solar gain through new Velux skylights often heats the place in mild weather. Their gas bill is trivial now.

OTOH, my BIL built his place from scratch back in the early 80's with staggered 2x4 construction, Pella Windows, foam exterior wrap, tyvek. They heat it with their attached greenhouse a lot of winter days. Maximum fuel usage in NY has been about 2 cords, and often less.

I agree. You need to consider your objective. If you want a super efficent modern house, then build one. Its not just the effort and expense of making an old structure meet these standards, I also think that by the time you are done so little of the original is left you often cant tell the house was old to begin with. (for good examples go to building science and look at their deep energy retrofits).

And then their is the embodied energy in constructing that new house. My house may not be close to a new house in monthly energy consumption but if you consider lifetime energy footprint it looks a lot better as it was built before the age of fossil fuels with mostly manual labor and renewable materials.

At the end of the day, I live in an old house because I love history and want to preserve a piece of it. I also want to conserve and do as much as I can to make this house efficient without destroying the original details that give it its history. But not at the expense of removing the details that make this house what it is.

 

[GaryGary]

Hi,
You can use this calculator to get an idea which areas of your house leak the most heat:
http://www.builditsolar.com/References/Calculators/HeatLoss/HeatLoss.htm

That way you can work on the most cost effective areas. Its simple and easy to use and you can easily play around with different improvements.

A blower door test is about the only way you will be able to get an idea how much the infiltration losses are -- they can be quite large on older homes.

I think that getting down to something like passive house standards on a existing home is really tough. To give an idea, have a look at what Gordon did to his house to get close:
http://www.builditsolar.com/Projects/SolarHomes/SchoolHouseRetrofit/Main.htm
I think he did an amazing job, but its probably more than most folks would want to do.

I'd try to find the worst of your heat loss areas, and work on the ones that are most cost effective to fix.

The book Insulate and Weatherize by Bruce Harley is really good.

Gary

 

[firebroad]

FWIW, I had icynene foam injected into my exterior walls. Cost a bundle, but it is "Green", and effective. It can be done on just about any type of structure--my house is slip-stone (flagstones mortared onto cinder-block). Make sure you hire a pro--this is not usually a DIY job.