Home working heating one room suggestions

the theoretical difference between a 50C return temp (pretty normal) and a 40C return temp (really pushing things) is 3% of theoretical efficiency.

I dispute that 50C is normal. It's been quite a challenge to get mine down to that level, because my boiler is rubbish at turning itself down. The difference between a badly set up system and a well set up one could easily be 8% in my house even if you aren't short cycling which will bring it down even more.

8% of a £300 monthly bill (for some, not me fortunately) is still a significant amount of money.

I plan to do an experiment in the coming days if I can find two days of similar weather. I'll try heating the house as it is, then I'll go and turn all the TRVs down manually and compare the next day.

thats the diagram that talks about lowering return temp. Not sure how it applies to a tanked (non-combi) system where the feed temp will be at least 70C anyway (to get the tank hot enough to avoid legionellas). I guess the flipside is that by not maxxing out the boiler (into non-condensing mode) when running the hot tap, you water heating is a lot more efficient.

Not sure how it applies to a tanked (non-combi) system where the feed temp will be at least 70C anyway (to get the tank hot enough to avoid legionellas).

There's a Heat Geek video about this too. 60C is enough to kill Legionella instantly, but 50C is enough to kill it in 2hrs, so it's plenty. It also says that tanked systems are far harder to optimise because you still need the flow temp high for the hot water even when heating it to 50C as the coil in the tank can only dump so much heat. The only way round it is to have a boiler that knows when it's heating hot water rather than rads and turns itself up.

I'm going to avoid this by using a timer on the immersion heater to heat the HW cheaply overnight, but I can only do that because I have an EV tariff. If/when the car goes back I might have to investigate hacking the boiler to allow the flow temps to be turned up and down digitally so I can automate it.

he difference between a badly set up system and a well set up one could easily be 8% in my house

how did you get to 8%? you would have to drop your return temp from 116C (Which we can all agree is unlikely) to 40C return temp.

Assuming you're not sending boiling water out, the hottest you can push out is maybe 90C, which (for a 20C drop) gives a 70C return temp - around 87% efficiency. if you can get that down to 40C (unlikely with the same rads) you would see a 5% saving. Yes, that could be significant, but not nearly as significant as the savings in only heating one room in your house. Fortunately, you can both reduce the flow temp and only heat one room

With my system turned up I got output temps of 75C and return temps of 65C which corresponds to about 85% efficiency, and with it turned down I get maybe 45C return temps for most of the cycle giving me 92% or so, so maybe 7% difference in efficiency.

I can't get a 20C drop across the boiler. If I turn the flow down to allow more heat to be lost from the water in the rads, then the output temp goes up because it's also going more slowly through the burner so it gets hotter, and this ends up raising the return flow temps as well. I did get close to a 20C drop by restricting the rads to lower the flow even more, but that was tested during the day. It might actually go over 20C when it comes on first thing in the morning and the boiler manual tells you not to have a drop greater than 20C - but it doesn't explain why, so I don't know if it damages things or not.

My boiler is widely regarded as one of the worst ever made though, and I don't have an intelligent flow/pressure sensing pump either which means it's just about the worst possible condensing setup out there.

molgrips boiler woes. again...

I think your 65C temp would be more efficent than that, but there's an easy way to test. Measure the water coming out of your condensate drain. For each litre that comes out, you've saved around 7p in gas (compared to running with zero condensing).

But when the rest of the house is cold you need to use more energy to keep one room at a higher temperature than the rest. And who has a completely uninsulated house? If you actually watch the video the “basic thermodynamics” are shown to be anything but.

By heating one small room you're losing energy to the rest of the house, and then to the outside. By heating the whole house, you're losing all the energy to heat the small room + the rest of the house.

It's more efficient to just heat the one room.

I use a wi-fi oil filled rad in my (not very insulated) garden office and it does the trick. I have it come on at regular intervals to keep damp away from the computer etc. Albeit, Ive reduced those intervals recently

It’s more efficient to just heat the one room.

In terms of heat loss, yes. But your CH system will be running less efficiently if you do just heat one room, that's the point. Possibly significantly so. Whether or not that cancels out depends on a lot of factors.

Also if you turn off all the rads except one, you may damage your boiler unless there's a bypass circuit installed. If there is, you're just paying money to pump a few hundred litres of hot water around a loop whilst only a small part of that is actually being used to heat the room.

Whether or not that cancels out depends on a lot of factors.

Anyway the point is there are so many different factors in house design/insulation, boiler type/rad arrangement, room usage, etc it's ridiculous to say "this is always going to be the case" (even the HG don't say that on their site) especially given people here have actually been monitoring their gas consumption and reporting the opposite!!

Although I will turn our boiler flow down, as it's pretty high, I can see how that'll make a difference!

If there is, you’re just paying money to pump a few hundred litres of hot water around a loop whilst only a small part of that is actually being used to heat the room.

not disagreeing that some hot water is being pumped around. Its not hundreds of litres though - that would require nearly a kilometer of 15mm piping. However, that water is pumped around whether you're heating one room or the whole house, so unless you're heating none of the house, the point is rather moot.

Similar but unrelated......

Empty house in a cold area (and poor insulation) with all rads with Smart TVRs (Tado in this case) set to frost protection.......is it cheaper to let the system do it's thing with the rads calling for heat relatively frequently throughout the day as they bounce off the frost protection temp; or is it cheaper to put the heating on for the whole house for an (guessing here) hour in a nice boiler effient burst to raise the temp up enough that it might last until the next programmed warm up without anywhere calling for heat. I'm think the 1hr burn would win.

Re the WFH single room issue - regardless, keeping the human in the room warm seems to be the win here with the room heated as little as possible. So heavy jumpers, heated blanket, maybe even fingerless gloves and a hat. Those duvet slipper things.

Empty house in a cold area (and poor insulation) with all rads with Smart TVRs (Tado in this case) set to frost protection…….is it cheaper to let the system do it’s thing with the rads calling for heat relatively frequently throughout the day as they bounce off the frost protection temp; or is it cheaper to put the heating on for the whole house for an (guessing here) hour in a nice boiler effient burst to raise the temp up enough that it might last until the next programmed warm up without anywhere calling for heat.

Frequent-ish to a lower temp rather than once a day to a higher one is best - the lower the average temperature over 24 hours the less heat lost. But all radiators together is best to reduce cycling. I expect that setting all the Tado's to heat to 6 or 7 degrees for 15 minutes every 4 hours might do it. They would then all come on together and switch off once 7 degrees reached one-by-one. Depends how quickly the house cools as to how often and what temperature is best. You can tell from the Tado reports what the radiators have been doing.

Bg engineer told me to leave heating on all day on frost protect, 7 degrees I think, as house is left empty for a long time. Setting the timer, as he said, is academic as cold periods can happen at any time. Worked so far, boiler not had to do anything.

Bg engineer told me to leave heating on all day on frost protect, 7 degrees I think, as house is left empty for a long time. Setting the timer, as he said, is academic as cold periods can happen at any time. Worked so far, boiler not had to do anything.

That is effectively what a smart system set to frost protection is. But I question it's efficiency. Sure, it stops damage, but a system bouncing off the frost temp will, in a proper cold snap, having it coming on and off many times a day. With the smart system this is even worse as each room can call for heat independently magnifying the calls. My theory (and sl2000 above seems to agree -ta) is to preempt the frequent calls by raising the temp a bit above the frost protection level once, or a few times a day with a boiler efficient blast.

Obviously this is a mute point if it's not that cold outside...but for context where I live we did not see a positive Deg C temp day or night from Dec 24th 2020 to Feb 14th 2021 - so 7 weeks of sub zero 24hr a day. The loch half a mile away froze to 8 inches thick. At those kind of temps frost protection in an empty house (and energy efficiently sorting it) really comes into play.

An IR panel would be good for just heating 'you' at a desk - MrsF has one next to her and she feels the cold. Fairly low wattage and they are usually temperature controlled from a remote - so you leave that near you !

Thanks, think I'll buy a small oiled filled radiator and continue to wrap up in layers and blankets, sadly wooly hats no go for the number of online meetings I have, although I'm going to move the kettle upstairs through the day time, every little helps

Podcast referred to above costing small elec heaters v central heating was sliced bread, r4.

All this argument over technicalities of heating - when the answer is insulate the room you are in as best you can....

The main boiler controller (so Hive in your case) and the radiator thermostats need to be the same brand / system – so you need to buy Hive TRVs, or replace your Hive controller with a new Tado one.

Not necessarily; without a Tado boiler controller the TRVs can't turn the boiler on, but they can still turn off the radiator they control so it won't do anything when the central controller turns the system on. This can still be useful if you want to heat a central bit of the house always and specific rooms sometimes.

We ran some Tado TRVs with a Nest central controller for a while before we fully migrated to Tado. If you've already got a system that supports TRVs I don't know why you'd do this, admittedly...

Do you need to hear the room?
I bought some lined trousers and sometimes wear a battery heated gilet when it cools down. With the heat from the laptops end electrics it keeps me plenty warm enough to function

Just another thought, what about something like a Kotatsu? Sounds very STW niche friendly.

sliced bread, r4.

That's the one. On a slightly different topic and related to the pod cast I'm wondering about a ceiling mounted IR panel in the garage. Current heater us a fan heater which as the podcast notes gets very addictive and then you overheat only to be cold again when turned off. Anyone any real world experience of IT heating panels.

Tje obvious answer is a new PC with one of the Nvidia 4090 cards in. They can draw 600w, so aim the exhaust at yourself while you work and let the graphics card warm you. Or, when/if it catches fire, let the fire warm you.

continue to wrap up in layers and blankets, sadly wooly hats no go for the number of online meetings

Yes It wouldn't be good to fail a workplace suitability assessment via teams......

Interesting article on the beeb over the weekend about the effects on the brain trying to work in low temperatures....

Interesting article on the beeb over the weekend about the effects on the brain trying to work in low temperatures….

Do you mean this one? Linky

If so, then I read that article, and wasn’t sure if I missed something but it seemed to be looking at the health issues of living at 10degC without whilst wearing a thin, short sleeved unbuttoned shirt and shorts. I didn’t understand then and don’t now - surely that’s a study into the effects of wearing unsuitable clothing, not of temperature?

Manual TRVs here, I turn the ones in the other rooms off manually. One advantage of not having many rooms.

Measure the water coming out of your condensate drain. For each litre that comes out, you’ve saved around 7p in gas

Is that true? Doesn't the bulk of the condensate get exhausted with the flue gases, hence the plume you see from boilers?

Just listened to that BBC podcast.

For now, it looks like I will keep using my oil-fired CH with EvoHome TRV's. Whenever the heating is on, both our towel rails in the bathrooms are on too so at least towels etc dry too.

Those infrared panels looking an interesting proposition, but they didnt compare the cost of them.

The other option is maybe the diesel heater? I've seen a lot of installs in sheds, workshops and houses

Worth taking a look at the FB group

I installed one recently in my van. It's been awesome

Is that true? Doesn’t the bulk of the condensate get exhausted with the flue gases, hence the plume you see from boilers?

Isn't the plume from vapour that condenses in the flue or outside, so doesn't contribute to the heat output from the boiler?

I suppose theoretically condensing 1l of water releases 0.7kwh of energy, which at 10.3p/kwh is 7.2p...

I hadn't thought of it that way before. This makes me feel better about the times I've been splashed by our boiler's condensate pump that is meant to empty into a gutter but does it a bit too enthusiastically so it sort of goes everywhere...

We have solar panels but no battery storage (yet). My working from home in a single small room involves a small 500w oil filled electric radiator that I turn on during daylight. The panels, even in winter, can generally supply enough power to run the a 500w heater. Power from the grid obviously kicks in when the solar output drops below 500w.

The radiator is under my desk by my feet.

Also, hoodies and slippers.

Not sure how it applies to a tanked (non-combi) system where the feed temp will be at least 70C anyway (to get the tank hot enough to avoid legionellas).

This is why we just upgraded our system to Priority Domestic Hot Water. Twice a day we tell the hot water to come on, and this tells the boiler to output 70C water while a valve ensures that the water goes only to the cylinder. Takes about 20 minutes to get the cylinder up to temp, then the valve closes and the boiler goes back to 55C for the central heating (see chart below).

We've got a full evohome setup with 9 zoned rooms, but my WFH default is still a small, 650w oil-filled radiator tucked under the desk by my feet, with a thick blanket covering my legs to trap the heat in that area.

No figures to back it up, but my thought was running the GCH just for one room is less efficient and costlier than what I'm doing. However, when other rooms/zones have their programmed heat on (kitchen and family area before school) I've got the office zone 'on' then to give the room a boost. Room I work from is far less than ideal being north-facing with 1.5 external walls, high-ceiling stone-built mid-late1800s, but it's all I've got available to me.

Also thick slippers and wearing an extra fleece over my hoodie. Only my hands that occasionally struggle with.

Don't forget gas is a third the price of electricity. So heating one room to needs to be using not power to be cheaper than just heating the house with a gas boiler.

Using electricity for heat to whether it is a room, a kettle, or a tumble drier is hugely expensive compared to other uses.

Don’t forget gas is a third the price of electricity. So heating one room to needs to be using not power to be cheaper than just heating the house with a gas boiler.

I know, that's the bit I need to get figures for. Not entirely sure how I can work it out with any degree of accuracy to compare heating the one room for WFH with my 650w oil-filled versus GCH via evohome.

Separate point but just taken delivery of some fingerless gloves to help with the cold hands. I feel so old now.

Edit:

Electric heater @ 650w on a thermostat for 8rs/day (assuming it's 'on' 50% of the time due to thermostat) @ 33.76p/kWh = (0.65 x 4) x 33.76 = 87.78p. So call it 90p/day to heat my office via electric oil-filled radiator.

I just need to isolate a similar outside temp day to measure kWh used if I heat the office via GCH single room via evohome. Our gas unit price is under a third of electric (33.76p vs 10.28p).

Not entirely sure how I can work it out with any degree of accuracy to compare heating the one room for WFH with my 650w oil-filled versus GCH via evohome.

Smart meters, I guess.

No figures to back it up, but my thought was running the GCH just for one room is less efficient and costlier than what I’m doing. However, when other rooms/zones have their programmed heat on (kitchen and family area before school) I’ve got the office zone ‘on’ then to give the room a boost. Room I work from is far less than ideal being north-facing with 1.5 external walls, high-ceiling stone-built mid-late1800s, but it’s all I’ve got available to me.

If you listen to that BBC thing above though it states that all the portable solutions cost roughly the same to use in the end. ie an oil rad is just as expensive as a fan with heating element (which feel more expensive)

Isn't the problem for most WFH people, myself included, the fact that you're sat still on your arse and not moving around all day? Same as sitting on the sofa infront of the TV on an evening. I've found that if I get too cold then even just getting up to walk around and make a coffee or running up and downstairs a couple of times makes a big difference. Walking the dog on a lunchtime keeps me good for a couple of hours afterwards.
My home office is only an elaborate cupboard with a window at 1.2 x 2.1m, just big enough for a desk and chair pretty much. We had it built recently as part of an extension and I purposefully kept it small so it would be easy to heat. Just keeping the door shut means that it is about 2 degrees warmer than the rest of the house after a couple of hours just from my body heat and background computer heat (only a laptop and 2 monitors so not a huge amount).
I did have the fingerless tramp gloves on yesterday morning though on what felt like the first properly cold day.

As I'm the only one at home today I tried using the GCH instead of my oil-filled radiator. Not what I expected.

Last week: 650w electric oil-filled radiator under my desk to heat me for 8hrs like I've been doing the past couple of years (estimating 50% actually drawing power with the thermostat clicking on and off):33.76p/kWh = (0.65kW x 4hrs) x 33.76p = 87.78p/day*

Today: GCH** to heat only the room I'm working in, no other gas use in the 5hr period 8.30am-1.30pm, used 1.923m3 gas = 21.85kW of gas in 5hrs. 21.85 x 10.28p = £2.25 for 5hrs only, that's not my full working day! Outside conditions around 2degC colder than the day I compared with last week although it's pertfectly still compared to a tad blowy last week, that's surely not enough of a factor to account for that difference.

I think I'm back to using the electric heater now that I know.

* No smart meters or plugs here and too much other leccy use to be able to isolate my oil-filled radiator use, hence me estimating the power usage based on rated power.

** Glow Worm Betacom 4 30C boiler, 30kW, ErP 94% A rated, new in Nov 2018, with Honeywell evohome controller with all rooms zoned except bathroom and WC rads.

My home office is only an elaborate cupboard with a window at 1.2 x 2.1m, just big enough for a desk and chair pretty much.

That's what I'm heading towards. Current 'office' is 4x3m-ish, high ceiling, large DG windows and doubles as a gym/storage/dumping ground. Trying to convince Mrs a11y we empty the upstairs 'cupboard' so I can stick my desk and chair in there: 1.9 x 1.8m, partly under the eaves with a small, ancient single-glazed skylight. That's got to be a more sensible (efficient) approach.