Should there be thermal insulation between floors in residential construction?

[maurice]

Hi.

I live in a 40 year old bungalow in Edmonton, Alberta, Canada, up north where the winters are very cold. I've got three forced air furnaces in my house, one that heats the basement, one the main floor, and one the addition. All of the furnaces seem to work just fine. I've been in the attic, which is insulated uniformly with wood chips. I will blow in some more insulation once I've finished some potlights and wiring, but the insulation is likley adequate up there (the snow on the roof doesn't melt any faster than the neighbours, and actually a bit slower than most, which is generally a good sign).

The heat in the addition and the basement are just fine. However, parts of the main floor are always cold, especially the living room, which has some pretty big windows and, though it has three heating vents, is the farthest room from the furnace. I figure it will always be a battle to heat it.

Anyway, I am doing some work in the basement, and the ceiling is mostly open during the reno. The previous owners insulated every interior wall cavity in the basement, as well as the entire ceiling, with fibreglass batts. They were musicians / music teachers, and I assume they insulated everywhere more for sound than anything else. I haven't removed the insulation, but it occurs to me that perhaps with a warm basement, removing all of this insulation would make for a warmer main floor?

Just wondering if anybody out there has any experience on this, or an informed opinion? thanks in advance for your help.

Maurice

[Sev]

How is air flow through those vents in living room? Ducts may need cleaning. Since basement ceiling is open, can you see any problems/ leaks in ducting? Blower may need checking. I'd also see what you can do to improve insulation/airtightness on those windows. Just covering them for winter with those window film kits to create extra air layer may help.

[Joseph Meehan]

maurice wrote: ..

Well if the basement is warmer than the first floor then removing the insulation would help. If it is less warm, it would hurt.

[maurice]

Basement is definitely warmer than the main floor.

As for the ducts, I had them cleaned very recently, which didn't help. No obvious leaks, but there is pretty weak airflow through them. I actually partially close vents in other rooms to try and boost the air flow in the living room, but it doesn't seem to do much.

[Edwin Pawlowski]

If the basement is warmer, and you have a separate furnace down there, just turn the thermostat down. Insulation is doing nothing, really, it is a matter of balance. You won't get any "free" heat upstairs from it.

[maurice]

The basement never seems to get cold, we don't have the thermostat very high down there.

But the insulation must make a difference - I figured that heat rises, and can't rise as efficiently if the ceiling is insulated. Just wondered if anybody had experienced this, or if there was a heating contractor who'd encountered this problem.

[Joseph Meehan]

It is not "free" heat because without the insulation some of the heat (a small amount) will move upstairs and then the basement will get cooler calling for more heat. I suggest that unless you need the heat down there, turn it down as far as it can go or turn it off.

[Joseph Meehan]

That sounds like maybe there is some sort of flow problem How are the filters, clean free flowing? Does the fan offer more than one speed?

It may require an on site inspection by a pro to find the real issues. It can pay for itself.

[Justin West]

You may want to check the balancing of your duct work. There is a search you can do on canada's NRC site, called the "garbage bag test". Essentially you take the bag, place it over a register and time the amount of time it takes to fill it up. From there, you can start closing a vent off that is quick to fill, and open a vent that is slow to fill.

Another option you can look at are little fan units that are inserted into your registers in a cooler room that is not receiving that much air flow.

And yet another option you may have is to install electric baseboard heaters in the one room to enhance the heat when required.

This assumes you've exhausted all the obvious things to ensure it's not a leak, bad equipment, etc....

[jJim McLaughlin]

You had a lot of thoughtful answers through out the thread, but the best one is the one aout the living room windows.

You have themal loss there. The windows are the one "odd" feature in the cold room. Thats a big hint

Your best bang for the buck is to increase the window effeciency.

Clear plastic cover outside over entire widows beginning in late October, say at Thanksgiving , through April?

Clear plastic inside over entire windows beginning late October, again say at Thanksgiving, through April?

Replace windows in 40 year old house with modern triple pane glass windows.

You need to cut the thermal loss throgh the widows before you think about boosting the haet flow into the room. Regardlesss of how much you boost that heat low, you are going to be putting that heat outside until you correct the windows.

[Tony Hwang]

Hi, Let me ask first what is your typical winter gas bill? You did not say how big your house is. My fully developed 2 story house in Calgary built in the mid-90's to my spec, runs on one furnace and winter gas bill is ~100.00. Very warm in winter and cool in summer inside this house. Your house was built B4 the time of updated building code re: insulation. Spend some money and do an energy audit, then you'll know what you need to do most economically.

[Tony Hwang]

Hi, Energy audit always shows window is the worst heat loser. Now our local builders are using triple glazed Argon gas filled Low E windows more and more. Cost little more but worth it for the long run,

[maurice]

Some good help here, thanks.

In terms of the windows, it's a bay window in that room, and was added about 25 years ago (according to the date stamp within the sealed unit). It's a relatively big window, but it's only on the one wall; the family room, by comparison, is warmer despite bigger windows on both walls. I will try the plastic, mind you, and see if that helps. good suggestion.

I hadn't heard of the "plastic bag" test, and will try that. I suspect that I'm simply not getting enough airflow into those ducts, and if I can correct that problem, that will be a significant improvement.

The house is a 2200 s.f. bungalow, so I'm heating 2200 square feet upstairs, (including the 200 s.f. addition), and 2000 feet in the basement. My gas bill in the winter is roughly $175 per month. The addition is very poorly insulated (it's one of those sunroom things, and the ceiling is half windows), and even though it's got a beautiful cedar interior with awesome curved laminated cedar beams, I'll likely remove the room next year and convert the space to a deck. I've been hoping to come up with a lake lot or rental property that could benefit from the extra room and relocate it, likely as a non-heated sunroom, but haven't found a place for this addition yet.

I'm undertaking renovations, and windows are on the agenda in the next couple of years, but I truly think that my problem is more heat related than heat-loss related. The windows don't frost at all, they're not particularly cold to the touch, and I don't get a draft at all. I know that's not a perfect test, but it's what I have done so far.

I think I'll try removing some of the insulation under that portion of the house and see if that helps. Also use the tests recommended to check for actual air flow through those ducts.

Anybody know how effective those "in-duct" fans are? And are they relatively simple to wire to the furnace? Do they cause any other issues?

Thanks.

[Tony Hwang]

Hi, My house is 2400 sq. ft. two story plus basement. And 200 sq. ft. all season sun room made out of open deck which is part of family room now. This room has R40 floor and ceiling. Walls are R20 plus all half height windows and sky light. Things grow year round in this room. You may try a booster fan which fits into a duct to increase air flow to the liing room. Luckily my bro-in-law is HVAC specialized PE. He is a big help. I am old school EE back (class of '66 retired)

[nicksanspam]

The sun room might collect more solar heat for the house if it had less thermal mass and an insulated wall between it and the house, so the sun room could be cold at night, losing less stored heat through the low thermal resistance of its windows. A fan might circulate air between the sun room and the house when the sunroom is warmer than 70 F and the house is cooler than 70 F, or when the sunroom is less than 40 F, to avoid freezing plants.

Nick