brant

Dehumidifier.

We’ve got one of those for drying clothes during the winter, but don’t tend to run it in the house as a general rule.
I think at the moment, with the warm-ish days and cold nights, the air is a bit ‘wetter’. It normally sorts itself out to a more acceptable level in a week or two.

I have been saying for years about getting a PIV unit installed to try to help with reducing moisture levels. We are planning on getting our hall, stairs & landing redecorated when we have an extension put in next year, so I think we will get it fitted while that’s being done.

Had that deep in your bones feeling cold all evening so had to fire up the wood burner for the first time.

A hot bath is quicker and probably more efficient for that.

I think at the moment, with the warm-ish days and cold nights, the air is a bit ‘wetter’.

Unlikely. Warm, indoor, moisture laden air is just condensing on colder surfaces over night, because the nights have got colder.

We have friends who live in the foothills of the Pyrenees and they use dehumidifiers in winter as dry air feels warmer than moist air and it’s very moist all year round where they live.

I think at the moment, with the warm-ish days and cold nights, the air is a bit ‘wetter’.

Unlikely. Warm, indoor, moisture laden air is just condensing on colder surfaces over night, because the nights have got colder.

Are you confusing moisture content of the air with relative humidity?

Went to bed last night and the house was 19C, woke up to a frost and the thermostat saying 17.5, feeling very smug about the cavity wall insulation we had installed back in 2019!

Heating should have come on at 17.5, but it’s a smarth-ish thermostat so it doesn’t come on if it’s marginal and it knows the house will gain a couple of degC from sunshine, the conservatory, towel rails/hot water system.

Still tempted to get a dehumidifier and plumb it in under the stairs in the hallway. We still don’t have a kitchen extractor so must produce a fair bit of humidity so that recovered heat might keep the house warm on marginal days like today?

I’m sure we’ve been over this many times in this thread already but what part of having a fire in your house is not having heating?

Depends:

Are you Ray Mears living in the woods – then it’s heating.

Are you sat in a chair on your phone, charged from a plug socket? Then it’s not heating, it’s just middle class hygge that happens to produce heat.

Still tempted to get a dehumidifier and plumb it in under the stairs in the hallway

Oh, this is a brilliant idea. A plumbed-in dehumidifier! I could put one in the loft.

EDIT oh, apparently they have a maximum ambient temp, too hot in the loft in summer.

Went to bed last night and the house was 19C, woke up to a frost and the thermostat saying 17.5

I turned the heating off before bed last night, room temp was 19c, by morning it was down to 14c 🙁

Was fine in bed but had to boost it back up today… currently at 17.6, relative hunidity at 57%

Central heating on yesterday and again today, but I had company and was feeling a bit sniffly.

Put the CH on last night, jeez I feel such a wimp as had intended to aim for the end of the month.

Put the CH on last night, jeez I feel such a wimp as had intended to aim for the end of the month.

😀

I was hoping to hold off until November but I’ve had to scrape ice off the car for the last two mornings, so the heating is most definitely on.

I’ve got as far as bleeding the radiators (only one had air in!!) and the boiler service is booked. The dehumidifier is now on the landing when not being used for clothes drying. Was a bit nippy yesterday morning – thermometer in living room said 15.8 degrees, but by the time the sun had come out that soon went up to 18.9. Mrs Fazzini comes from the same school of CH thought as my mum did (and by default therefore me too): Cold? Put a jumper on. Still cold? Put another one on 😂

I’m going with jumpers and blankets, house temp is generally 17.5 or 18 which I think is about as low as I’d want to go.

i like to go as long as possible without putting it on, regular topic of dispute with mrs ex-punk.  but tonight i’ll make an exception cos my little grandaughters coming over to stay for the night and we cant be having my little sweetheart getting cold 🥰

tomorrow itll be back to an igloo.

Still not getting the fact that people make a significant investment in equipment to keep them warm then take great pride in not using it.

Unless it’s for financial reasons it seems to be a strange sort of masochism.

Unless it’s for financial reasons

Mine is *very* much this

*IMPORTANT UPDATE ALERT*

First time in the loft. 50mm of insulation now topped up to 350mm.
BUT

Also noticed 3 full to exploding bin bags abandoned by previous owner. Full of Lego!!! Star Wars sets, Lego animals, bricks etc

JACKPOT

My day is made. As you were…

Unless it’s for financial reasons it seems to be a strange sort of masochism.

Lol, if it wasn’t for financial reasons, my thermostat would be 19/20c, 24/7/365

The significant investment in heating and insulation etc, is also for financial reasons as in theory, over time it will payy off as it will cost ‘X’ less to keep the house at ‘Y’ temp.

Leave it off for as long into autumn as possible, again financial reasons.

my thermostat would be 19/20c, 24/7/365

I’m lucky enough mine can be 18/20/21 all the time.   I still got annoyed when yesterdays cold winds blowing through London in exactly the right direction to blast through bathroom window vents cost me £4.51, my highest daily gas bill since May. And for a double whammy we we weren’t in to benefit, we were standing the Velopark freezing our toes off – despite the sun -marshalling a Duathlon.

I’m using my central heating this year if needed. Kitchen is currently 11°c so I might turn it on for a few hours. 

Last winter I made it to December before using my central heating. Taking the chill out of the air in the morning will probably benefit me more mentally rather than challenging myself to see how cold I can get. 

Log burner will be used less this year and the money that I didn’t spend on wood briquettes will go on the gas bill instead. 

I’m wondering if I would benefit from another layer of loft insulation, current insulation is level with the joists..not not sure if it would affect ventilation too much?

I’m half tempted to hire a thermal camera so I can check all over the houseand I’m not just shooting in the dark, but they look to cost about £100 per day to hire…

I’m wondering if I would benefit from another layer of loft insulation, current insulation is level with the joists..not not sure if it would affect ventilation too much?

That’s bugger all. My 2007 build came with about a foot of insulation, and I added another foot not long after we moved in. Quite a big difference in warmth feel, even before I was paying that much attention beyond general; but also made a huge difference to outside noise coming into the house and it’s not even a noisy location.

A modern new build house will have about 400mm of insulation in the roof. I’d aim for that but be careful that you still have the loft ventilated.

Still not getting the fact that people make a significant investment in equipment to keep them warm then take great pride in not using it.

Whilst I do like to keep the bill as low as I can (better things to spend the money on), I also like to consume as little fossil fuel as I can without going full hair-shirt.

EDIT oh, apparently they have a maximum ambient temp, too hot in the loft in summer

Do you really need it in summmer…?

Do you really need it in summmer…

Yes, it can be humid in the summer as well!

I’m half tempted to hire a thermal camera so I can check all over the houseand I’m not just shooting in the dark, but they look to cost about £100 per day to hire…

You could just spend that money on more insulation instead.  AFAIA loft insulation gives the biggest payback – after that probably comes walls (if you have solid 9″ walls then you’re a bit pooped without large expense) and windows, which are also very spendy.

Check for drafts just by checking doors and windows with an incense stick!

If your with OVO your going to see an increase in payments as they want winter paid for by the end of march rather than being spread over 12 months, that’s over an £100 per month increase for me.

If your with OVO your going to see an increase in payments as they want winter paid for by the end of march rather than being spread over 12 months,

Don’t they all work to end of April normally anyway?

Build up credit over summer, work through it over winter to be roughly zero balance by end of April.

so- boiler flow temperature vs length of time it takes to warm a house up to the desired temperature.

Pretty much every energy saving website says its best from an efficiency point of view to lower the flow temp of your boiler. Given that flow temp affects how quickly a house warms up, is that blanket guidance correct?

ie if at a flow temp of 60deg c it takes your house 3 hours to warm up to your desired temperature vs 1.5 hours if the flow temp was set at 70 deg c, does it still hold that the 60deg C flow temp uses less gas overall? Anyone got any good links that talk about this, or know the maths to prove it one way or the other.

Asking because this is the scenario I find myself in – 60deg c flow temp takes 3 hours to hit target temp , 70deg c takes 1.5 hours – similar outdoor ambient temperatures (1deg c) and similar starting temperature and target temperature, but which temperature uses less gas overall?

If you have a system that works at a fixed flow temperature then lowering it is going to save gas, as it’ll always be heated to that temperature (or off).

Finding the right point is a bit on an experiment. When I had a system like this, I just started at 70 and lowered it by one degree each day until I felt it was heating up at an acceptable rate and cold achieve the set point.

If you’ve got a system that modulates the flow temperature and/or has weather compensation then it’s more about the heat curve (which dictates that flow temperature given an external temperature and a set point) and a max flow temperature. Because the system will adjust the flow temperature within the bounds determined by the heat curve. In this case you want to be starting high and then lowering to where it can achieve the set point. If it’s too low, and can’t achieve the set point it stays on and burns more. If it’s too high, it’ll overshoot and can get into cycling on/off, not condensing and lowering efficiency like that.

TL/DR – start high, and lower it very gradually till you’re not comfortable, then raise it a touch.

does it still hold that the 60deg C flow temp uses less gas overall?

In principle yes up to a point, because the cooler your flow temp the cooler the return temp and more heat is extracted from the gas; the less heat is leaving your house via the flue.

However it’s complex because your radiators can shed a certain amount of heat from the water which depends on their temperature (and that of the rooms) and your boiler has a lower limit on the amount of gas it can burn. Mine is shite and has a minimum of 9kW which is more than the radiators can get rid of at 50C or even 60C.  BUT the flow water starts off cold.  So it puts in 12kW (the max) but the water doesn’t reach 60C straight away, it takes a while to warm up, during which time the house is also getting warmer even before the flow temp is reached.  When it is, if the house still isn’t up to temp, the boiler will start cycling.  If this happens on a 3 minute cycle or more, it’s not too bad for efficiency, but if it’s every 30s then it reduces efficiency.  So the lower flow temps are more efficient but that could be off set by short cycling.

Depending on your boiler it might have a variable output pump, and it might be controlled by the boiler itself (mine isn’t).  A good modern boiler can have a nice low flame and a slow pump which means that the water hangs around in the radiators long enough to get nice and cool so the return flow temperatures are nice and low, and it could be super efficient.  So in that situation you want to set the flow temp as low as you can so that the house gets warm – after all, it might be losing heat at 3kW on a cold day but if the boiler is throttled down and only producing 2kW of heat, you’ll get cold.

Mine is always producing a minimum of 9kW so I have to work out how to get that heat out of the water and into the house.  I’ve had to fit bigger radiators for this purpose and it has helped a fair bit.  Eventually the boiler cycles, so when it gets colder I may need to turn up the temperature so that more heat is output.  However, the flow temp would increase by 10C and the return temp by say 8C (because more heat is dumped at a higher temperature) but the return temp would still increase, and that is what reduces efficiency.

Also, if you are running lower temps it takes longer to heat up so you may well be better off not letting it cool down as much overnight – they call this the ‘set back’ temperature.  I have now gone with a set back overnight of 16 and daytime of 17.5, and the span on the thermostat is 0.5C.  Because it’s warmer for longer in theory you would lose more heat but this could be offset by more efficient running. And you can get away with a lower temp too whilst still feeling comfortable.  You aren’t just warming the air with your heating you are warming everything in it – floors, furniture etc.  So if you let it get cold overnight and the floors get cold, the boiler will work hard in the morning to get the air warm and switch off but the floors/chairs etc will still be cold so you will want a higher air temp to feel comfortable.  If you keep it largely the same temp all the time it will feel warmer even at a lower air temp setting.

Got it?

I didn’t even know they made combi boilers with such a low output as 12kw. 

Most are 24-30kw heating for a 3 bed 2 bath house.

What make/ model is it? Surprised it’s not firing constantly if it’s modulating as well . Even a low modulating model will run down to 1/3 so it would only be generating 4kw , across an entire house.

Mine isn’t a combi, I have a water tank. It’s the smallest boiler in the range, but they all have the same minimum flame so the 35kW one modulates down to 9kW, but so does my 12kW one. And 9 is too much.
Modern ones can modulate down to like 1.5kW which would be perfect for us.

I’ve no idea what I’d do with 35kW. I guess it would heat the circulating water up almost instantly then throttle back to the same figure.

Most are 24-30kw heating for a 3 bed 2 bath house.

Most combi boilers just surely.

Heatings off tonight but the stoves on.

Heating has kicked in a couple times the last week or so mostly as the kiddos room has dropped below the set point when at -2 outside temp.

Put CH on just for an hour tonight mainly as I have manflu. The wad I spent on the loft in April seems to be working as the house is really retaining the heat.

ie if at a flow temp of 60deg c it takes your house 3 hours to warm up to your desired temperature vs 1.5 hours if the flow temp was set at 70 deg c, does it still hold that the 60deg C flow temp uses less gas overall? Anyone got any good links that talk about this, or know the maths to prove it one way or the other.

Asking because this is the scenario I find myself in – 60deg c flow temp takes 3 hours to hit target temp , 70deg c takes 1.5 hours – similar outdoor ambient temperatures (1deg c) and similar starting temperature and target temperature, but which temperature uses less gas overall?

Think of it as a thermodynamic system.

Energy in = energy out

Energy out = conductivity x surface area x differential temperature x time

Therefore any time spent at a lower temperature is reducing your energy bill.

It’s also why letting the temperature drop overnight is cheaper, because those hours the house is at a low temp overnight it’s losing less energy than it would if it was warm. Also why dropping the thermostat by 1C saves about 10% off the bill, it’s on average ~9C outside, average thermostat is ~19C, knock 1C off that, the temp differential drops by 10% and you’re reducing the energy transfer by 10%.

Unless it’s for financial reasons it seems to be a strange sort of masochism.

Why am I being kink shamed?

Until then though, I just don’t feel ‘cold’. I can quite happily sit around the house down to about 15-16C and if I feel cold then I get up off the sofa and do some batch cooking, tinker in the shed, go for a ride, etc.

It’s also why letting the temperature drop overnight is cheaper

That’s the simple model. But there are multiple other factors that might mean that’s not then case.

That’s the simple model. But there are multiple other factors that might mean that’s not then case.

Unless your boiler/system is massively inefficient, combined with a house that didn’t lose much heat then it holds true. For Joe Blogs in a normal house with normal gas (or electric, or oil, or LPG, or wood fired) heating it’s correct.

It won’t be true if you have storage heaters (obviously, that’s their whole principal). And might not be true if you have an ASHP and underfloor heating and a discounted night rate (because that’s potentially a wet storage heater with an efficient daytime mode). But for the other 90% of housing* it’ll hold true.

*Not a made up stat for once on the internet, 5% are on storage and 5% are on “other” which I took as ASHP. https://www.statista.com/statistics/426988/united-kingdom-uk-heating-methods/