Sedentary indoor cold wear

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horsewoman
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Re: Sedentary indoor cold wear

Post by horsewoman »

We live in an old rambling (stone) farmhouse, and have only our kitchen, living room, kids bedroom and office heated (central wood stove with hot air wents to the rooms upstairs).
The rest of the house is not heated at all, or with an electric space heater in case of the tiny bathrooms. @jacob is very right to point out out that European houses are very different to US ones when it comes to insilulation - our house is a fortress compared to my cousins (very nice) house near Boston!

I have been living like this for 15 years now and by now I have excellent thermoregulation. DH and I wear always at least 2 layers in winter inside and top up with hoodies/cardigans when we are in the unheated areas of the house or when the wood stove is not yet firing in the morning. I'm seldom hot or cold, inside or outdoors.

We do have a four poster bed but I only have mosquito netting up in summer. We prefer warm duvets and a fleece blanket, that's toasty warm even in our alpine winters.
One learns to change clothes very quickly, it is not so bad after getting used to it.

This is my second winter where I don't use electric space heaters in the bathrooms - actually all it took was a conscious decision not to use it, and I'm never cold. One saves a lot of water and electricity by simply being quick about one's business :)

Our teen daughter is never cold, she runs around barefoot in shorts and t-shirts year round at home (we have -8 Celsius at the moment!) - ikd if it is a personal trait or an sideffect of going up in a house like ours?

jacob
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Re: Sedentary indoor cold wear

Post by jacob »

@mathiverse -

You're probably familiar with how the side [of your body] facing a fire place feels warmer than the side facing away. That's radiative energy.

In an insulated home, you can feel where the radiator is. However, the radiator will also heat the inner walls, ceiling, and floor which will be substantially warmer than the outer walls compared to an uninsulated house. Since you're receiving radiation from all sides, you can lower the air temperature itself without feeling colder or uncomfortable.

The air itself heats by conductive heating. That's very inefficient (verify by sticking your hand into a warm oven. If the home is uninsulated, the inner walls will be quite cold and your body will have a negative heat balance. This is compensated for by increasing the air temperature using central air.

The way that temperature is measured usually does not account for the radiation component.

Sometimes people will get a small heater or a fireplace in their uninsulated home. That's still not as comfortable since you'll still have a "cold side" and that to humans is uncomfortable.

TL;DR - It's similar to how it feels warmer sitting in the sun than in the shadow given the same temperature. If you want to feel equally warm, you have to increase the temperature in the shadow.

@UKwk - Convection (air mixing) is how the non-radiative heat spreads most effectively. W/o it would take a long time since air is a very good insulator. If your radiator shows up on an infrared camera (it does), there's radiation getting through. If it was absorbed in the air it would be hidden like in a fog.

AxelHeyst
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Re: Sedentary indoor cold wear

Post by AxelHeyst »

To add to that, UKwk, if i don’t have the specs on a given radiator i assume it’s giving off 2/3 of its nameplate heat as radiant heat, and putting 1/3 of its nameplate heat in to the air via convection. It’s not nearly that simple in reality and depends on mean radiant temperatures of the surfaces in line of sight with the radiator and air temp and blah blah. So the short answer is that radiators give off both kinds of heat. This is also complicated that some people call “radiators” which are actually “baseboard convection units”, which do what it sounds like. Not everything long and along the bottom of a wall is a radiator.

eta: keeping the feet and the head warm are key for thermal comfort. The head is easy: warm hats! Feet can be tricky if the floor is cold. This is one reason why radiant floors are so amazing. I’m considering some sort of indoor rated mukluks, as i almost set my shoes on fire warming them up with my propane heater the other day (indoor temp=40F/4.5C) and my warm boots are muddy/outdoors only.

white belt
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Re: Sedentary indoor cold wear

Post by white belt »

@AxelHeyst

Check out military cold weather boot liners. They can be found at surplus stores or online. It’s worth giving them a shot before shelling out for a separate set of boots just for indoors. They can be paired with warm socks as well. Here’s an example I found on google but they can be found all over:

https://colemans.com/u-s-g-i-extreme-co ... boot-liner

UK-with-kids
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Location: Oxbridge, UK

Re: Sedentary indoor cold wear

Post by UK-with-kids »

What I'm calling a "radiator" is just a sealed metal container on the wall with hot water inside it, and that hot water is being constantly being replenished with new hot water at the same temperature as it gets pumped through the system. This is by far the most common system in almost all UK homes.

According to the calculations on this blog post - https://edavies.me.uk/2014/08/radiators/ - the proportion of heat given off as radiation is likely to be in the region of one sixth to one fifth of the total, i.e. the vast majority comes from convection. My "radiators" should probably be called "convectors" instead.

That does also accord to the reality that I'm feeling in the house. You typically get one large radiator against one wall of the room, typically in the coldest spot like under the window. So it's not unusual to be sat at least 2-3 metres away from the radiator. A common question might then be - "is that radiator even on?" as there is zero feeling of radiated heat like you'd get from a fire or the sun in winter for example. It probably doesn't help that the radiators in our house are only warm to the touch, i.e. you can hold your hand on it comfortably, so it's definitely not at 70C (158F) as mentioned in the article I linked to, and the graphs in that article confirm that would reduce the amount of radiated heat coming off.

Regarding flooring, old houses in the UK usually have what's known as "suspended flooring". That's a wooden floor suspended above an airspace of about 2 feet in height to allow for air circulation and to prevent damp from condensation. Obviously that makes it very cold underfoot.

white belt
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Re: Sedentary indoor cold wear

Post by white belt »

So far here have been some unintended benefits of lowering my thermostat to 60F (other than the obvious that it saves energy/money):

-We've had a couple of days with highs in the upper 50's/low 60's (I know that's like summer time by northerner standards), which means I can open my windows and get fresh air on those days.

-I feel more acclimated to outdoor temperatures. It's not as jarring going outside even on a cold day.

I may further lower to 55-57F. I had to bust out my extreme cold weather military gear, which is essentially like wearing pants and a jacket made of sleeping bag material. I take off the jacket if I'm cooking or doing something more active indoors, but the pants pretty much stay on the whole day. I just wear a t-shirt, socks, and normal underwear underneath (no long underwear). I don't mind taking off torso layers, but I prefer just having one pants layer so there is less changing. The also have the zippers going all the way up to the hips for cooling, but I haven't had to use them yet. See here for what I'm talking about (you might be able to find them used online or at a surplus store): https://www.youtube.com/watch?v=NTrqOP3IsEc

I look slightly ridiculous wearing gear that's rated down to like -40F (if I wear all of the under-layers which I'm not), but you guys are right that it's a totally different ballgame when we are talking about staying warm while sitting sedentary around the house.

Edit: Onward to 55F! This is the lowest my thermostat goes.

AxelHeyst
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Re: Sedentary indoor cold wear

Post by AxelHeyst »

white belt wrote:
Mon Jan 18, 2021 1:09 am
Check out military cold weather boot liners.
You just saved my piggies, which have been developing chilblains in the past week. Thank you!
UK-with-kids wrote:
Mon Jan 18, 2021 3:08 am
Touche. My "experience" is with modern commercial grade radiators covering a comparatively larger area in spaces that are actually well insulated and constructed.. and I never went out and measured the things myself, which is kind of a big problem with the design engineering industry but never mind. I don't know if this is the case where you are, but I've heard of old steam radiators being retrofitting to run much lower temperature water, which obviously makes them far less effective. (One steam radiator might have been fine when it was at steam temp, but at "warm to the touch" is essentially useless).

The other issue that you mentioned is with radiators being under cold windows (or if the space has cold air), so you have a dump of cold air directly on to the unit. That's going to increase the deltaT between radiator surface and air temp, which will drive up convective heat transfer.

I liked that article's conclusion - go with underfloor radiant systems! They work well with low water temps (120F/49C), and you can easily retrofit a suspended floor with radiant (as long as you take care to insulate under the tubing, otherwise you've just nicely conditioned your crawlspace...).

UK-with-kids
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Location: Oxbridge, UK

Re: Sedentary indoor cold wear

Post by UK-with-kids »

Just thought I would pop back into this thread with a further observation about radiators. We just moved house and we now have a much more effective heating system and the radiators are now much too hot to hold your hand on. I keep noticing that radiation effect that @Jacob mentioned of feeling the heat just from being in the vicinity of a radiator. That never happened at the old house with the colder radiators. I'm guessing they would look very different on an infrared camera as well. So I have two conclusions from that:
1. Radiators don't radiate heat at lower temperatures, they are almost exclusively convecting heat.
2. Setting the thermostat low isn't the whole story - if you're close to a properly functioning radiator then you could have the thermostat set low and still feel warm.

Salathor
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Joined: Fri Dec 18, 2015 11:49 am

Re: Sedentary indoor cold wear

Post by Salathor »

I know this is an old thread, but I just had some input in case anyone is still thinking about this. We keep our house at 60-63 (used to be 55 but couldn't figure out a way to reliably keep babies warm when they undress themselves constantly). My key that I found to keeping warm was feet insulation (wool socks) + reduced air travel. Wearing a thin windbreaker made a significant difference over even the fluffiest robe/hoodie, even inside.

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