Why is my guest room cold?

In My Humble Opinion
1

My house has an attached garage on the side of it, with a bedroom behind. I don’t believe it was an addition. It’s over a crawl space, whereas the rest of the house is over a basement. Of the 4 walls, 2 are exposed to the outside, 1 to the garage, the last to the house. The attic space above the house is not well-insulated.

When the weather starts dropping in temperature, this room gets very cold. We’re scheduled to get new windows (one on each of the outside walls) in the next couple months, but I don’t think that’s going to solve the problem. I can lay some insulation in the attic with, I think, little effort. I think the crawl space would be much more difficult - and I have a sinking suspicion that the crawl space is the problem here.

Any easy ways to determine where my heat is going?
Any trends that tell me that the attic is far more likely than the crawl?
Anyone want to roll around in my dusty crawl space on a random November Sunday?

2

Borrow a FLIR camera, and take a look at all surfaces - that should pretty quickly tell you which ones are the coldest.

3

A FLIR camera would make it super easy. Failing that, a laser thermometer can be aimed at various spots on the floor, walls, and ceiling to see if there are any cold spots.

Also, how is the room heated? Make sure the ductwork is connected, sealed, and insulated.

4

Heat rises, without good insulation its going straight up and out. Start there.

5

It’s always a challenge to keep these remote rooms warm. You’re fighting not only the room from losing heat due to the added surface area exposed to the exterior, but you’re fighting getting heat to the furthest place (usually) from the furnace. It would take a bit of experimenting with the duct vents but you’d have to close/limit the vents along the duct-work leading to that room and then leave the vents in that room wide open.
Or you could give up like I did and just run a small electric ceramic heater in the room to keep the temp up.

6

If it’s only used for occasional guests a electric space heater may be your best and easiest option.

7

Poor feng shui.

8

The bummer is that it’s now my COVID office for the 3 days a week I work from home.

9

Count me among those who’d rent a FLIR camera and just get medieval on the place.

+1 if your attic is poorly insulated, but that should never stop you from renting/buying a cool tool.

Then, if the crawl space is also vented and/or poorly insulated … you’ll get a stack effect that will hurt you, your neighbors, and the odds of any of us beating this COVID thing.

Word.

You’ll want to figure out how leaky the place is, and whether it’s worth your while to undertake some air sealing. Some municipalities offer free/low-cost energy audits.

If you’re serious about this room, a blower door test is the ‘legit’ way to figure out how bad your leaks are.

And … yeah … a space heater is often a cost-effective cure for a lot of ills … depending on use, cost of energy, and 358 other things.

Happy Hunting !

10

Is he sick ? Did he die ? I had no idea …

:wink:

11

What year was your house built? Some houses, like mine, were built with zero wall insulation.

Also, if you go the electric space heater route, I highly recommend an oil filled radiator. I have one kind of like this one.

12

I have rooms built over crawlspaces and they’re toasty warm in the winter.

I’m not an expert, so hopefully better-informed people will answer. I’ve faced some of the same problems over the years and often did the correct thing last, which means I’ve made a lot of mistakes before getting to the right answer.

When a room is too cold in the winter, it’s usually because the heating requirements weren’t sized correctly for the room, or the heat is not getting to the room.

In a most modern homes, which probably have duct work, it could be that a duct is blocked or there are not enough ducts/vents to bring the correct amount of warm air into the room to heat it properly.

Call in a HVAC expert for an assessment. They can get you started in the right direction. They can give you a quote for fixing it, or give you advice about how to fix it if it’s something you can do yourself.

As to attics, of course you want to insulate the hell out of them, especially in cold northern areas, but I find they are not a source of cold air infiltration into a room.

Yes, attics are cold and yes, heat rises. That means you are heating your attic, which you don’t want to do, but it doesn’t mean that the attic is what is making your room cold. You should insulate the attic aggressively when you can, but that probably won’t keep an under-heated room warmer. It will slow heat loss, which assumes you are getting the right amount of heat to begin with.

As to insulating a crawlspace - please don’t do it until you check with an expert in your area. Depending on where you live and the climate, it can cause big problems, like mold. Since your crawl spaces are underground and lead from the basement, they are probably not a source of the cold.

If your windows are not leaky or drafty, you can put off new windows for a bit. Do some googling on the R-values of new windows and you’ll see that new windows may not bring you much increase in efficiency. I don’t want to discourage the improvements, and you should get them if you want them, but they likely will not solve the problem with a cold room unless, again, the windows are very drafty.

Start with HVAC. Go from there.

Anyway, good luck. Working in a cold room is unpleasant. It’s like working in your refrigerator.

13

I have an old house with little to no insulation. By futzing around with the heating duct dampers, I can keep enough warm air coming in to the furthest rooms. It’s pretty finicky. My furnace installer “helpfully” reset them all for me and it took a couple days to get it right again.

And I second the use of portable oil-filled radiator heaters. Because of my old wiring, I can’t use most space heaters, but the oil-filled one on low or medium keeps any room in the house warm, even when my furnace was out.

14

Seconding this. Before we did our wall insulation, and got a new furnace, we had an energy assessment done. Our living room was always colder than the rest of the house. There were a lot of possible reasons: it has a fireplace, a huge divided light window, old front door and old double-hung windows, and a crawl space (but it’s open to the basement). We did a number of things, but I think the main thing that solved the living room problem was having the HVAC company switch the duct to the living room with the return from the living room. It put the duct that blows the hot air right where we sit, instead of right next to the hallway.

15

I also like oil-filled radiator heaters. They don’t work fast, but they are steady and reliable. I have one in my 20X40 ft unattached, un-insulated potting shed for winters. It’s not hothouse warm out there, but I’m still able to take my jacket and gloves off while working.

16

Haunted. Sorry.

17

I also want to second the oil filled portable electric heaters. I have one and use it in an underheated room.

In the case of that room, which is fairly well insulated, the radiator is way too small to heat the room, so I know why the room is cold. Once the budget allows and there are some strong young men around, we’ll move a bigger radiator in. If we use the room, we use an oil-filled portable heater. It does a great job.

As much as I love the oil-filled portable, its use does show up in the electric bill if it’s being used a lot. Still, it’s a decent compromise until you get the kinks worked out.

18

I have a similar problem in my master bedroom, where one of the forced-air floor vents is cleverly located midway along an outside wall, exactly where the head of a bed would go. Normally this would not be a problem, but I have a Scandinavian-style bed with a closed bottom section, which totally blocks the vent. I use a fan-type electric heater to compensate during cold weather, which I prefer to other kinds because I find the sound soothing. Oddly, the room gets quite cool in the summer from the central A/C coming out of the same vents, so no problem there. It’s just winter cold that is problematic, and the little heater perfectly solves that.

Electricity costs are not an issue for this little thing. I actually welcome the cool weather because the central A/C is the really big power draw.

19

That’s an important point, and one to which I was alluding when I talked about an energy audit.

Not many decades ago, houses were drafty. You just pumped heat into them in the winter to keep warm. But you didn’t have significant moisture problems – barring a leak – because everything could dry out.

There is a balance between air sealing/insulation and ventilation. Lots of different materials and techniques can be used to modify this balance.

That was why I was thinking energy audit (that should look at cursory HVAC issues), air sealing, and insulation.

If you have a vented crawl space and an uninsulated attic, you can knock down the stack effect by reasonably insulating the attic (ie, without sealing and insulating a crawl space that requires ventilation).

But you’d still need to understand whether, where, and how much moisture you might be trapping in the process.

Building science is huge these days, and – IMHO – pretty fascinating. It’s also infinitely harder than … pump more heat into the room (in the case of very leaky envelopes).

20

Another factor: where is your thermostat? If the space the thermostat is in has better heat or insulation, it will shut off the heat before the remote room is warm.

In our house the top floor is ‘open’ to the bottom except for a walkway between the bedrooms. So the thermostat for the upstairs is in the master bedroom. The master bedroom is over the kitchen, while the other two are over the garage and therefore do not get the heat from the lower floor.

As soon as we close the master bedroom door, the other bedrooms start to cool off. Even if the rooms were identical, if one room has two adult people in it and the other has a child, the child’s room will be colder than the master because 2 people throw off about 200W of energy which helps heat the room, shutting off the thermostat before the other rooms reach the same temp.

The oil heater is the simplest solution. The expensive solution is to add multi-zoning to your heat sytem using thermostats in each space and electric dampers to divert heat where it needs to go.