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Posting this in the hope that someone has the same issue as us.

We live in a 19th-century three-storey terraced house in the north-east of England. We converted the loft so we know that's well-insulated. Other parts of the building are not.

Every winter, the top floor (which includes a tiny home office) gets too hot so whoever is up there ends up opening the Velux windows. Meanwhile, downstairs it gets too cold.

The bottom and middle floors have bay windows so we have heavy blackout curtains. However, we don't want to keep those closed all of the time.

We have a Nest thermostat which has helped a bit, but what else can/should we do to be more thermally efficient? We've got a curtain across the front door and all windows apart from one are double-glazed.

Has anyone had success with things like window film? What else would you recommend?

(boosts of thread appreciated!)

@dajb I assume you have thermostats on your radiators? So you can control each room independently?

In terms of insulation the windows are usually the biggest culprits. They're double-glazed, but do they also close tight and are the sashes properly mounted?

I'd suggest you find someone with a Flir camera and take pictures once heating season starts. You should be able to see pretty clearly where heat leaves the building.

@fedops Thanks, our energy supplier (Octopus) has a scheme to hire a Flir camera, but they're all booked out now.

I should probably look into radiator thermostats that can talk to the Nest 🤔

@dajb we have simple programmable ones. Like in the bathroom they turn the radiator on from 6-8 in the morning. In the living room from 17-22. Different on the weekends.

The master thermostat also has a timer which is manually aligned with the radiator units which is a bit inconvenient but we never adjust them anyway. If there are requirements out of the ordinary we just flick it to manual.

@dajb we have the predecessors of these ones I think - half the price and without the Alexa bullshit. They work quite well.

screwfix.com/p/honeywell-home-

@fedops Cool, thanks, I'll take a look. All of our radiators are behind radiator covers (with foil behind) so we'd have to program them and then stick to it, I guess...

@dajb depending on your wall construction you might see quite some heat loss behind the radiators. If you have space adding even a few cm of Styrofoam with foil on one side helps.

@dajb @fedops When you borrow your IR camera, look at both inside and outside surfaces. Some heat-leaks are more visible from one side or the other. And wait till November before borrowing: you won't learn much during the summer.

Be aware that IR images are hard to read. For example, the rectangle on the centre-left of this picture is our (detached, quite unheated) garage.

@markusl @dajb I've noticed some of the outdoorsy smartphones now come with infrared cameras. Wonder how good they are...

@fedops @dajb Interesting! Is that thermal infrared or photographic? I recently learnt (here) that they use different wavelengths of IR, which is why people don't glow in artistic IR photography.

@markusl @dajb thermal infrared. Here's an overview of a couple Black view models (in German, alas):
chinahandys.net/outdoor-smartp

Photographic infrared uses filters for artistic reasons as you say. Basically the same thing we did with infrared sensitive film back in the day.

@dajb @fedops Two other problems with FLIR images. First, some surfaces radiate heat better than others, and show up as brighter. That doesn't mean they're leaking more.

Second, walls hold heat from the sun. Some of what you see is leaked heat, but some is stored solar energy. To minimise this effect, take photos late at night after a cold, dull day.

@markusl @fedops Sounds complicated! In reality, there's only three areas we can improve given that it's a terraced house:

- Front (including two bay windows)
- Back (could replace back door)
- Top (need a way for it not to get too hot!)

@dajb @fedops From the age of the property, I'm assuming it has single-skin walls?

@dajb houses of that vintage up to just before WW1 would have 60cm+ walls here which actually insulate fairly well due to the sheer thermal mass.

One thing that can be done is add interior insulation if the room sizes allow that. You need about 2-4cm for foam tiles and then add either sheetrock or something else over top of it. Great time to redo your wiring as well if you want.

Obviously only applies if you own the place.
@markusl

@fedops @markusl Yeah, we do own it although the walls (even between us and neighbours) are definitely less than 60cm!

@dajb @markusl if the top floor gets hot in winter it can really only be uncontrolled heating?

@fedops @markusl Yeah, probably:

Early morning: we want the whole house to be warm before the kids go to school and we start work

Later morning / early afternoon: we just need the top floor warm where my wife's home office is

Later afternoon / evening: we just need the bottom floor warm and the bedrooms a moderate temperature

@dajb @fedops You can get thermal underlay for carpets. I'm not suggesting you recarpet just for that, but next time you do...

@markusl @fedops Oh we ripped up almost everything in the bottom floor and replaced it with either wood (with reflective insulation underneath) or carpet (with decent underlay) so that's all good 👍

@dajb @fedops I was more thinking about insulation between storeys. Since different storeys need to be warm at different times, thermal underlay upstairs would help to maintain thermal isolation. Again, though, I'm sure it's not worth recarpeting: last time I looked, it was roughly equivalent to a 3-tog duvet.

I guess large, heavy rugs upstairs might make an incremental difference. We got our big fireside rug cheaply at a British Heart Foundation shop, so you could ask there.

@dajb @fedops @markusl I'm not familiar with Nest, but can it capture readings from other parts of the house, or is it running its program solely based on the zone it's in?
There are some systems that have wireless sensors for different areas and you can tell the system which ones you want monitored at what time for readings.
Obviously not a fix for your house (which sounds amazing), but I was curious.

@jeffnik @fedops @markusl My understanding from the reading I've done is that the Nest can't control the devices you can put on raidators. Which is annoying, as obviously (given the age of the house) it doesn't have different heating zones...

@dajb @fedops @markusl Gotcha. We have a single forced air system so we can't control the heating to the different areas except to manually adjust registers. The separate zones help with if you want your bedroom at 18C at night the system will ignore the temps of other zones at night and only run the system to try and get that area to where it should be. This can leave our basement frigid in the morning, but the 2nd floor bedroom is comfortable.

@jeffnik @fedops @markusl Yeah, it's pretty much impossible to retro-fit a system that works in an economical way!

@dajb
Years ago, a friend had the same problem and solved it by installing ducts with fans to circulate the air. Worked both ways: during summer it brought cool lower air upstairs, and during winter it pushed hot air from upstairs to the lower floors.

One problem though may be finding space to install the riser ducts between floors. My friend's was and easy case.

@65dBnoise Hmmm, I did think of something like that and it would seem it's doable - in a house that has some loft space for the pipes, etc. 🤔

@dajb May not be what you are looking for but the old Japanese approach is to heat where you are rather than heat the house. So electric carpets and blankets, space heaters, warm clothes, down comforters, hot water bottles, etc.

@Matt_Noyes Yeah, thanks - I've told the family that they will be using personal heating solutions (aka hot water bottles) this winter!

lowtechmagazine.com/2022/01/th

@dajb you may want to procure or rig a kotatsu - a low table with a built-in heating unit covered by a quilt and a glass table top. Very popular in Japan.

@Matt_Noyes Oh interesting! (I thought you were referencing the popular games website for a minute....)

@dajb I can't find it now, but there is an article about the evolution of the design that discusses the best type of heating unit to use. It would definitely work for a dining table (or a work desk) but you would lose the smooth transition from sitting to napping...

minimaljapan.com/best-kotatsu-

@Matt_Noyes Lol, I just showed my wife and she looked me directly in the eye and said "no".

So that's a maybe then 😂

@dajb I was reading about this the other day. I am unsure if it fits your situation or not. We're trying thicker blinds and film (for a velux) this year and hoping.

Otherwise, hot water bottles. Simple and very effective.

5-10% reduction - preheat disabled
theheatinghub.co.uk/articles/W

6-8% reduction with a condensing combi boiler - lower flow temp
theheatinghub.co.uk/articles/t

@athairbirb Oh interesting! That first link 404s for me, but the second one, I'm taking a look this afternoon!

@dajb I do apologise, there's some added gumpf for some reason, this one shouldn't 404 theheatinghub.co.uk/articles/W

I hope they prove useful to you over the winter

@athairbirb Boosting, thank you! Turns out we don't have the pre-heat function on our Potterton, and my wife had already heard (and set) the flow temperature, but hopefully it'll help someone else 👍

Seachaint's advice on applying window insulation film 

@athairbirb @dajb Film works but condensation can be a problem. So I recommend:
* Make sure the paint job is up to date to discourage damp entering through wooden frames.
* Make sure seal of glass to edge of frame is sealed also by pressure or sealant (applies only to classic windows probably)
* Before applying film, clean window thoroughly with dilute vinegar, wiping off until bone dry.
* Then direct hot air at the glass and frame to dislodge idle water molecules.
* Put a dry silica gel pack into the frame before sealing the film over the double-sided tape. A small one recycled from a post package is fine, just make sure it's dry by microwaving and/or ovening.
* Once the film is on and tamped down, put an extra layer of sellotape over the edge again before using heat to shrink the film. This increases airtightness and watertightness, and keeps the film from dislodging from the double-sided tape a month into winter..

I've done it a few times over the years and the above protocol is sound. Getting the hand of incrementally revealing the double-sided tape while applying the film is down to patience and experience. Having a competent helper would be nice, I never did. The silica and extra tape are new additions since last winter, and the windows prepared in that way are still sealed perfectly and condensation free heading into this winter. :)

It really does work, by the way. Even just by reducing opacity due to inner condensation on the glass. I'd like to try external magnetic tertiary glazing this year, too..

Seachaint's advice on applying window insulation film 

@seachaint @athairbirb This is amazing, thank you so much!

Seachaint's advice on applying window insulation film 

@dajb @seachaint @athairbirb

Nice! :D

Seachaint's description is the low-tech/homebrew version of how the double-glazed glass module panels are made in industry. :D

Seachaint's advice on applying window insulation film 

@seachaint GRMA!

@dajb the non-insulated parts of the house are letting hot air in, and as hot air is lighter, it rises inside the house up to the top, where insulation isn't letting it out. It also pushes any cold air down.
You have several alternatives:
1. Insulate the rest of the house, but that would only work as long as all windows are closed.
2. Make some opening at the top of the house to let the hot air escape, but it needs to be resealable in winter.
(...)

@dajb
3. Make the roof more thermally reflective. There are special coatings for this, but anything that's white will help.
4. Force the hot temperatures down by mechanical means, with a big fan or a heat pump, but the first option is noisy and the second one is expensive to install.

@dajb sorry! I read your problem wrong, as if the issue were summer hot air.

The principle is the same, but the solutions might differ.

Insulating the lower floors will still help, and even if there are films for that, the most sure option is double-panelled windows.

As I said, hot air is lighter, so it always will fill the house from top to bottom and push any cold air down first. A heat pump with radiators in each floor would help.

@dajb letting hot air escape from the top would be a bad idea on winter, but you might try something to trap the hot air down. Of course, in a loft that's harder said than done.

@hmantegazzi Yeah, it's a tricky one! We need the hot air to magically decide to go to the bottom of the house in the evening 😂

@dajb Useful things have been said and I miss a section/plan of your house to help better but I will go through without it :) Outdoor snares are a better option than curtains because the heat is stopped before it has entered the house. There's no single house in the south of Europe without snares (plus awnings in most cases). If you need inspiration, I'd look for Mediterranean solutions to this.

@fudguy I'm actually looking at the opposite problem - how to keep most of the house warm in winter without spending a fortune in gas/electricity.

(the top of the house gets really warm even in winter as the air rises, which is a problem, but secondary)

@dajb I see, I didn't understand the curtains were trying to avoid heat loss instead of avoiding insulation

@dajb Better isolation could be considered for the 3rd floor and adding controlled ventilation as @65dBnoise has already pointed out. I'm not in UK architecture and I'm not sure that I have fully understood the issue, but if the rooftop is flat, a plant cover with plain natural grass is a delicious and efficient solution (adding a small slice for a water cistern in case your area has extreme temperatures, which should not be the case at that latitude).

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