Just added insulation
My McMansion (1750 sq ft heated, cathedral ceilings, 3 story exterior and tiny yard, hate it) has not been the most comfy, and the utilities have been outrageous. So, I decided to have more insulation put in. The guy came out yesterday, measured at different parts of the roof and found that I had too little in the attic. My house is insulated with pink fiberglass blow-in in the ceiling, seems I had about 9 inches on average, making it about R18 i the roof, and should have had a minimum of at least 12 inches making about R27.
What was really surprising was the cost. 800 bucks to add about 9-10 inches of insulation. I priced out buying the insulation from Home Depot to do the job myself, it would have been about 1600 or so just to buy the material, then I'd have had to do the job myself. They just rolled in, shot the attic in less than an hour, and drove off with my 800 dollar check. With any luck this will knock a considerable amount off my heating and cooling bill. The way natural gas has been going I could very well see a payoff this winter on the insulation :thumbup: . Since this was surprisingly cheap to do considering what was done, might be worth looking into for some of the rest of you too. I'd been kinda leery about it because I was thinking 2-3 grand to have someone come in and do it. |
I live in a townhome situation...the unit I live in is an 8 unit building. Luckily, all my neighbors don't care about their bills being high. That means that my electronic thermostat that shuts off the furnace or A/C during the summer saves me a ton. I have three sides of my unit being warmed or cooled by those people. During winter, with the furnace being off from 8am to 4pm the house never drops below 62° and I only set it to warm to 68° in winter. During summer the temp can reach nearly 80° when the A/C is off, but the house cools down in 15 minutes to 74° when we get home.
My unit faces North so it has extra insulation in the attic (I still need to go up there and see how thick it is). I wish I could change out the windows in the place to more efficient ones. That might be the next thing to look into for your home, or at least putting new seals on them. I'm going to see how much it would cost me to put in new seals myself since they are the felt type seals that just slide into a channel. |
Thanks for the tip. We just had a new house built and the blow in cellulose insulation seems too thin. We were going to do the do it yourself route, but I guess we need bids now.
First I'll try to milk the 1 year warranty though and get it for free. |
Here's a related anectode :)
My family's house only had insulation around the attic access.. Basically, no insulation. We painstakingly went up in the roof, and marked 12 inches on every vertical truss beam. With a white grease pen to make it easily spotted. We had blown chopped/convoluted fiberglass put in, we paid for 12" - and we told the operators that we marked 12 inches on every beam and we'd be checking to make sure it was there. They were so worried about putting too little in, that they went over several inches over most of the house! They had to come back a second time to finish up because they ran out of material :p I forget the cost and I don't recall the square footage of the place (at least 2000) - but without high ceilings. But I do remember a rebate from the power company for a few hundred dollars. ----- Another big help for those with really hot attics is an active cooling fan. Even solar powered would be beneficial. Blow out some of the stagnant oven air and take in some ambient air ;) And finally, making sure you a/c ducting is covered by this new insulation is a good idea. If it's sitting on top of it, you're combating ambient attic temperatures when you could have a little extra insulation :) |
Yeah... I've been pestering my family about insulation, evaporative cooling, and vent fans. But why pay a few hundred bucks for all that when we can pay an extra $500-1000/year in heating/cooling bills? :rolleyes:
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Telco -
Good job. The Pink Panther (insulation) Strikes Again! Our < 1000 sqft home is from 1924 and has a flat roof and NO insulation. There is a small crawl/attic space, but no ceiling door into this space. Also, there are wood slat trusses going across maybe every one or 2 feet. To blow insulation in I would have to : 1 - build an attic door (probably in the closet, that's the normal thing to do). 2 - Figure out how to get the insulation uniformly installed *through* the trusses, if you know what I mean. CarloSW2 |
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cfg83 - Bummer on that. Might look into having the roof foamed. They will drill a small hole between each set of slats, then pump in foam that will harden. My dad had this done to a house he build in the late 70s, and it did an excellent job of temp control. Those of you with the cellulose, excellent. Cellulose is made of recycled newspapers, and is supposed to be a lot more eco-friendly than fiberglass. It also insulates better with less product. My 18 inches of fiberglass is the same as about 13-14 inches of cellulose. Only bad thing about the cellulose is it compacts down more than fiberglass, so you'd need to add a couple more inches sooner. |
when I was building houses we would put in 16-18" of blown in cellulose with a goal of R50-R55, it was one of the things that made the heating and cooling bills on these houses nearly non exsistent, if you have the space it makes alot of sense as it's not that much more time, and the insulation is cheap, and you are already in your atic with the equipment.
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I can't believe that no one has mentioned straw bale houses. These blow away all of the blown products. Pun... intended.
My parents have a house that is 7000 square feet. Now THAT is close to being a mansion. I still wouldn't consider it one though. You really need to break the 10,000 mark for that. Even so, my dad did a good job with insulation, so the energy costs there aren't all that bad. My future outlook seems to hold a straw bale or dome house in store... or a combination of the two!!! |
Telco -
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CarloSW2 |
Erdrick - I don't know about straw bale housing, there's a lot of disadvantages there. You've got to treat the stuff to keep mice and fires out, and replace the bales every so often. No idea how insurance might treat you on this, I know if I was an insurance agent I'd view a straw bale house as a fire waiting to happen.
An alternative for you might be to look at dry stack block building. I've been researching different building processes to find a cheap, sustainable way to build, and really like what I see with this. You can build it yourself, the walls act as thermal mass, and will be damn near tornado-proof. Another thing to look into, the solar heating shed. Collect sunlight to heat about 1000 - 2000 gallons of distilled water/antifreeze stored in a heavily insulated tank, then pump that water/antifreeze solution through the house to keep it warm inside. Use a heat exchanger to use the same system to keep the house hot water hot too. I figure the shed would make a great utility point, you can keep a full electrical system (think off-grid PV setup) inside the same shed as the water heating system, so long as you have a way to keep the electrical side heat isolated in the summer. In the winter, residual heat would keep the batteries at the optimal temp to provide power to the house. And, I plan to use a wood fired boiler for emergency heating. There's probably a week, maybe two, in my area cold enough that I might have to run it. I have more thoughts on this if interested, and tons of links put back, if interested. |
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Regarding foam insulation that Telco mentioned, there are many manufacturers now. I was considering a brand called Airkrete, which is supposed to be more environmentally friendly than the urethane foam insulations like Icynene. Any foam insulation saves 40% - 50% more energy than fiberglass or cellulose because it eliminates air infiltration, the major cause of heat or cooling losses. |
Telco: I appreciate the links. I will be sure to look into those two building techniques. A word on straw bales though. According to the sources that I have gathered information from, straw bales, if properly packed at the source, and dried, are more flame retardant than your average building materials. I don't remember the specifics, but they definitely outperformed conventional building materials when subjected to a fire test. There is also no nutrition in them, thus deterring any rodents (and especially bugs) from taking residence in them. Again, it is key that the bales are very compressed, so that there are no air pockets in them, and there is no moisture left in them. As for longevity... if they are properly sealed, so that no moisture can get into them after installation, then they can last for a reallllly long time. There are historic homes from back in the 1700s and 1800s that were built with straw bales... and they are still standing.
So, I would suggest taking another look at straw bales for use in home building. I think that if done right, that they can be an excellent alternative to conventional building materials. |
Oh... links! :thumbup:
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If you can afford it, concrete walls, then a continuous XPS inner layer - maybe 4" thick (but it is a case of declining returns so choose whats best for your climate and pocketbook), then internal wood framing for the inner walls and floor joists (you could still use rock wool batts for interior or exterior stud walls for sound deadening and also some internal zoning if needed or firebreaks - the XPS already is serving as the vapour barrier). XPS under the slab or in the middle of a slab sandwich and then a roof with minimal thermal breaks. The walls will be pretty thick.
If you can eliminate thermal bridging and build it tight enough (that you'll need a HRV/ERV), you're heatloss will be extremely low. Best thing is to keep the house small so that the internal gains can be best used. If 6 cattle will keep a barn's foundation from freezing in the great white north imagine a superinsulated sub-1000 sf home with a couple of big slobbering Newfoundland dogs using renewable energy in the form of dog food doing about half the heating! ;-) |
2ton - Blueboard is nice, spray in is better, especially with new construction. I'd not hesitate to use the blueboard if I were putting new siding on a house, but new construction may as well go whole hog.
My own plan also counts on no insulation on the interior walls. Concrete is a pretty good soundproofer on its own, and the thermal mass should contribute to a warmer house in winter. Should be able to manage about 2000 sq ft with no monthly heating expense, too. At least, this is the goal. There was one company building huge houses, 3000 - 5000 ft, that used timber for the thermal mass, these huge houses are heated and cooled for about 25 bucks a month in Colorado. No idea what the name of the company was anymore, but they had some impressive looking hunting-lodge looking places. Insulating the interior walls would defeat this. |
Telco, spray is better for many applications, especially using stud cavities but spraying an even coating on the bare concrete walls and then having to clean everything up for the studding afterwards... *trembles*
Thermal mass is your friend and your foe... the in floor radiant crowd loves it on the inside of the insulation envelope. It takes a while to get it up to temp and then after that forget setting it back unless you'll be away for weeks. Just watch out for solar gain. My preference is to have the mass on the outside - hugely beneficial in flattening out the daily outdoor temperature variations although it would do much more for a home at altitude in NM than here, but still. As for the interior, I like low mass. Combine that with TRV's panel rads sized for low water temps and you have a house that is responsive to changes in internal gains and losses whether or not they are intentional. How is the house being heated for free? Solar? |
2ton, I'll have to give that some thought. Everything I've read about mass says that it's useless if you insulate the inside and not the outside, and I can see the point. The mass would be cold in the winter and hot in the summer, and would fight with the inside. Insulation is not a true heat block, it resists the movement of heat, so having a thermal mass against the insulation on the outisde would either be a heat source or a heat sink accelerating the movement of heat through the insulation. Having the mass on the inside means the mass will be less affected by the outside, so should emit or draw more from the room and less from the outside. This would mean a more regulated interior temp. Yes, it would be harder to change the interior temp, but this is what you want. Once the temp is set to a comfortable level, it should work to maintain that level with small inputs.
Yep, solar is free. Since you have to pay for whatever method is used, that part is pretty much a wash. Maintenance is also required on all systems, so that is out. I'm basing that off the monthly operational charges. The only time the system would not be free is if I had to burn wood during deep winter, or had to run a backup generator. Check out the solar shed idea for how I plan to gather and use solar heat for the house. That fellow was able to keep his house warm a lot further north than I am using only the sun. |
Yes, the golden rule of heat transfer is that heat energy will transfer to anything with less heat energy and all insulation can do is slow it down.
That solar shed is nice although I'd be tempted to add sliding doors of some form to limit gain. Solar can be very tough to control and by the time you have enough for the winter you have to have a great strategy for limiting it in the sunnier warmer periods and also have a good way to dump all those excess BTUs if you get caught off guard. I'm fond of geothermal... in essence it is already stored solar energy. Howver if truth be told, if I could get peak consumption low enough like 1 or 2 BTUs per SF per heating degree day, I'd probably just use an electric boiler off the grid and try to ensure it uses offpeak power. Right now I use a condensing gas boiler and I'm around 5 BTUs per HDD per SF which still is good, considering the fact I can't do much about my walls, although they are insulated. Probably far cheaper and simpler for control and materials required than going solar. I'd still try and have some form of solar preheat for the water heater. Have you seen the newer evacuated tubes that are becoming more common in Europe? |
Evacuated tubes? Nope, new one on me, but it'll make a nice research project for tomorrow. Luckily my job allows me some free time due to computer lethargy (centralized programs used by thousands of people, lots of lag time on the server side) to research personal things while waiting for the computer to catch up. Multitasking rocks :D.
The fellow that put that site up suggested building the solar wall at 90 degrees instead of 70 degrees to help limit summertime exposure, that combined with an overhang that will cover the top half of the panel in summer and none in winter might be plenty for this. Might have to play with the roof on this, perhaps design the overhang so that it allows a flap to be extended to cover more or less of the panel, much like a jetliner's flaps extend out? Such a setup could even be computer controlled. It wouldn't take much power or a very heavy overhang to do this, perhaps enough to cover from 40 to 60 percent of the panel in the summer. So far as dumping the excess, I'm figuring the large water tank would be more than enough to help moderate the temp. Such a large mass of water would take time to heat up and cool down. I am also a geothermal fan, but only on a commercial scale. I used to be hot on those ground loop heat pumps, till I discussed it with an HVAC contractor. He said his customers who have bought them usually wind up having to replace the ground loop within 3 years or so. While the ground loop tubing is under warranty, that warranty is parts only, not labor. They have to use a special kind of glue, in layman's terms, to install the loop so that it will properly transfer heat with the ground, and it's almost impossible to get it back out. His customers usually wind up replacing the ground loop system with a high SEER heat pump for the same amount of money as the ground loop repair, and get an entire new system. I deal with the guy on a high performance automotive board and his shop is somewhere down in Louisiana, so there was no ulterior motives on his discussion of them. |
Wow, those evac tubes look great! Much better than what I was planning to use. Course, more expensive, but looks like they'd work a lot better so might reduce the need for a wood fired boiler (not that I'd ever want to not have a backup). Thanks for the tip!
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Incidentally, plaster is no barrier to mice. Don't know about stucco. Edit - Did a little searching, looks like it's not the easiest thing to get approval for. New Mexico is the only state that allows it. Go here for more information on straw bale housing, very informative article that shows potential problems and cures, and the direction of straw bale housing. Pretty surprising info. I still plan to build with cement though. |
There is no problem building straw bale homes in Minnesota or Wisconsin. Historically mice aren't a problem. Don't badmouth something you don't know anything about--and I was referring to whoever told you these untruths about strawbale as "nuts", not you personally. But you shouldn't be spreading rumours and half truths as the gospel.
But, to get back more on-topic, I have been talking to a few homeowners and builders who have been having problems with blown-in fiberglass as attic insulation and are finding that it doesn't pack down enough when blown in to prevent infiltration, and some folks are experiencing freezing through a foot of fluffy fiberglass because of its porosity. They are finding that blown cellulose is giving better results in the real world, because it packs down a bit and isn't as loose. For walls, in a stud wall, I would seriously consider one of the foams or sticky fiberglass or cellulose products to fill all the voids. |
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Blown in fiberglass wasn't my first choice, it was what was in the house when I bought it. It's not recommended to put cellulose on top of fiberglass, and I wasn't about to pay to have the whole house cleaned out and cellulose put in. This house is as insulated as I plan to make it as 2 years from now, I'm out of it. The insulating guy did say that he's having a hard time getting blown fiberglass though, said that the insulation companies are moving to cellulose for their main product. |
WisJim -
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Last year we looked into the Nasa-Style "Foam Roof". I know it would have gone a long way to solving our problem, but it is based on petroleum products, so the cost was pretty high last year. Here is an example : https://www.socalfoam.com/ EDIT : It was between $6K to $10K for our < 1000 sqft flat roof, depending on the thickness. We were also a worried about toxicity/allergy issues. Technically, it's inert, so it shouldn't be a problem. But, you probably wouldn't know until after you experience health problems. CarloSW2 |
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