How you heat your home depends largely on how you live in it as much as the construction. If you are up and about for a couple of hours in the morning and then in the evening, you only need the heating on long enough for it to come up to the temperature you want, then to maintain that. Twice a day.

All the other things add up too. Remember that any draught is uncontrolled ventilation and you want to reduce them so you aren’t heating the street.

interesting one for me this: I’ve a large detatched house with two bathrooms and a growing family, currently a 20+ year old system boiler and tank

How old are the rads as well? I’v replaced the rads in two house renovations and massively improved the system efficiency. Modern rads are more efficient and you might be able to reduce pipe lengths as well if the existing installation isn’t well thought out. Make sure all the rest of the easy wins (insulation, draughtproofing etc) are done as well.

I’m only trying to help. Listen to molgrips if you want.

No don’t, I’m not offering advice, just trying to figure out why the real world experience seems to contradict the physics of it. There must be something I’ve missed.

Molgrips – your boiler and or system are poorly designed if your boiler only runs for a minute or two when it comes on. Probably the boiler is too big for the system and pipework

That is a distinct possibility. Our house is well insulated and all the rooms have TRVs. There are three small ballast rads in the hall and each landing, the top two are almost off because it gets so damned hot up there. We’ve got the house fairly comfortable all round, and that’s how the boiler operates.

Can it be throttled back I wonder? Maybe the water temp turned down?

Yep. Night set back is a common used energy conservation strategy. 13degC is the usual set point.

Seems like the mechanics of how the heat is delivered and distributed around the house counteract the simple solid body model.

If you are up and about for a couple of hours in the morning and then in the evening, you only need the heating on long enough for it to come up to the temperature you want, then to maintain that.

Isn’t that the opposite of what Wrecker says?

Combis, pahhhhh……. horrible things (suit some situations)

How come? Not trolling at all, I genuinely have no idea, and had believed the whole ‘they’re more efficient’ thing.

What’re the thoughts on radiators vs underfloor heating?

I’m about to move into a new (old) house, which has an old boiler and water heater; ultimately it probably all needs to be replaced in the name of energy efficiency, but I’m like a baby at a Chelsea game – completely lost.

If I had a hot water tank I’d be looking at solar water heating. If you’re considering underfloor heating then that works well with solar heating too – but only if you’re planning on staying put for a while, otherwise the install cost is unlikely to be covered whilst you live there.

Isn’t that the opposite of what Wrecker says?

Wrecker is largely talking about commercial properties – very few houses have the sort of thermal mass he is talking about. A relatively modern and / or well retrofitted property should be fairly quick to bring up to temperature as it shouldn’t lose that much heat anyway. Also, most people dont have multi-temperature thermostats so they would end up heating the house at the same temperature all the time. The evidence is that very few people touch any part of their heating system throughout the day/week/month as well.

I’m about to move into a new (old) house, which has an old boiler and water heater

Depends on the house. If it has wooden floors then you’d be looking at having to replace with something like (low cement) concrete to have the mass.

How old are the rads as well? I’v replaced the rads in two house renovations and massively improved the system efficiency. Modern rads are more efficient and you might be able to reduce pipe lengths as well if the existing installation isn’t well thought out. Make sure all the rest of the easy wins (insulation, draughtproofing etc) are done as well.

rads seem fine and may be more modern than the boiler, TRV’s fitted

house insulated within “normal” parameters, cavity wall and loft

How would you define modern rads in years? 10 years?

Thanks. 🙂

“most people dont have multi-temperature thermostats”

No excuse for that though. Other than ignorance, lazyness and fear

So cheap and easy to fit in most cases. Mines was 35 quid.

I stick it at 20 for 4 am till 5 am kick back to 14 till 5 pm and stick it to 17 when iget in i put the stove on if it cold. 6pm it kicks back to 14 till 4 am again.

House rarely gets below 16 the now.

just trying to figure out why the real world experience seems to contradict the physics of it. There must be something I’ve missed.

I think it’s an overshoot problem. We’ve got underfloor heating. If we turn it on to 20 when the room temperature is 15 it fires up… and 3 or 4 hours later the room is at 20 and it switches off. However the floor now has loads of heat stored and continues heating the room well above 20. What we need is a more intelligent controller. What we actually do is keep the temp pretty constant all day.

I ‘m an installer ( one or two on here have had me work in thier homes and a couple are awaiting quotes etc)

the best way to save money is not to have it on.

the best way to keep you and your family warm is have the heating on.

the two do not marry easily.

i ve said before but its a simple set of rules.

before spending money on upgrading boilers controls keep the cold out and the heat in.. get rid of draughts, ( i ve put a new front door threshold and compression draught excluder in my own home this week ( 14 quid screwfix) and the temp has risen noticably in the hall.., when its windy out go round every window pane you ll be amazed at the cold / draughty spots you ll find) insulate the loft insulate the walls ( it wont be any warmer but heat loss and therefore energy req to heat home will be reduced.

I differ here from bear in that i believe heating a big tank of water twice a day is a waste especially if you dont use that much each day..
so if you one of STW singletons or a couple hot water cylinders probably arent the way forward.

if on the other hand you have a large family (4 or more in the house) or you insist on a shower head the size of a steering wheel then a tank is more suited to your ‘needs’

any house will be warmer with the addition of new effcient and internally clean rads.

then i’d consider trv’s

then i’d consider a quality boiler ( i only install Worcester, more expensive than some quality in the last half dozen years has been first rate. i d ensure it was protected with a magnetic filter)

then i’d go to town with controls..

then i’d turn it off to save money.. 😀

dont forget to understand exactly what your usage is.. only two out of my many customers actually measure thiers. When you are absolutely clear on what your usage is THEN and only then consider changing supplier as a few hundred kwh can make a difference on which is the ‘right’ product / company for you.

from prior experiance of my last 2 houses being that type of construction…… YES once our stone houses got cold holy hell it took forever to heat them back up.

Ours are 3 foot thick, but luckily we’ve the best part of a foot of insulation, otherwise we’d never get the house warm.

In our last house (pretty modern and well insulated) as long as the thermostat never dropped below 15c, the house never got in the least cold.

The only way to both reduce cost and keep warm is to insulate as much as possible; porches etc also really help. And don’t underestimate the ‘aspect’ of the house.

The only way to both reduce cost and keep warm is to insulate as much as possible

Agreed, walls, roof, windows, doors, everything. Then buy a hat.

totalshell – thank you very much for posting, most useful info. 🙂

Can I just come back to my question of radiators? At what age should they be replaced for efficiency purposes?

I stick it at 20 for 4 am till 5 am kick back to 14 till 5 pm and stick it to 17 when iget in i put the stove on if it cold. 6pm it kicks back to 14 till 4 am again.

Problem there is that the thermostat is in the hallway. We don’t live in the hallway. We live either in the living room or bedrooms depending on the time of day 🙂

Can you get individual thermostats for each room? I know you can get moveable ones but that won’t work well with TRVs.. or will it? Hmm…

Totalshell – can you get me about 2ft of that flexible plastic pipe and a connector? Apparently it’s hard to get small bits, you can only buy 25m rolls trade…!

Wireless rf with reciever in hall and thermostat in roof your in ?

Tootall is bob on, my experience is on large office buildings, distribution centres, supermarkets and manufacturing facilities. Some may be relevant to residential buildings, some may not. An understanding of thermal transmissivity and emissivity may be an advantage to older building owners. At any rate, I only meant to try to add some perhaps less common knowledge. Totalshells experience is far more useful and relevant than mine.
I will say that there is no such thing as a standard building, I am yet to see an accurate calculation or program to give optimal settings to controls ( and I’ve seen many large consulting engineers try). Trial and error is the best way. Measure, monitor, manage is the mantra of the energy institute. Learn how your bills are calculated (and see how the providers take the piss with changing CV). If it interests you, look at degree days. From my point of view, I don’t care if people are motivated by lower bills or want to lower their carbon debt. As long as they do it.

forgot one of my favourite bugbears..

get asked regularly to increase size of rads etc.. move the sofa, so its not in front of it.. we must have the warmest sofas in the world..

dont have the curtains hanging over the rads when closed or even when open. use a blind to window sill height. leave the curtains open.

modern rads would be less than 10 years old and include a convector element ( the wavy bit behind the panel) kep em clean inside by keeping the water clean. if you have a power flush INSIST that each rad comes off the wall and you see it stood on end and washed out ( we took a shovel of silt from a rad that had been ‘powerwashed’ only a month previously)

keep rads and boiler debris free with a magnetci filter ( fernox pref, 80 odd quid from screwfix)

dont use the thermostat as an on off switch..

did i mention turn it off.. at least turn it down can you tell the difference between 19 degrees and 20 degrees

dont use the thermostat as an on off switch..

Dont get me started.
Radiators and boilers. Radiators don’t heat by radiation and boilers don’t boil.
Engineers indeed.

No excuse for that though. Other than ignorance, lazyness and fear

What thermostat for a smug saddle on a tall horse?

The vast majority of the population don’t understand/don’t care/have ‘a method’ regarding the use of their system. Most customers aren’t as enlightened as you and most builders/installers aren’t either. Lots of people haven’t taken up the insulation grants that could make a bigger difference.

wrecker – my tutor is working on a funded PHd around supermarket design and energy use. Really geekily interesting (especially the bits about not including the freezer and fridge aisles in the overall design or energy use).

Its warm ob my horse though.

Been helping my neighbour with insulation in her gaff . She let slip she spends 2k in oil a year !

Still only has the insulation the house was built in the 50s with

100% agree with insulate before heating

Have lived in rentals with dumb thermostats and its amaizing how much oil you use compared to a programmable one.

Perhaps its just in my nature as an engineer to research shit i think isnt right . Where as the mrs would rather just pile money at the on buton than invest in efficent and automated kit.

Well. Just had my first nights sleep with this new boiler. Or not.

The pump that sends the waste water out is intermittently making a right racket. The airing cupboard is next to the bedroom, and it was ‘whu-whu-whu-whu-whu-whu-whu’ all night.

dont use the thermostat as an on off switch..

The guy said this was the best thing to do. He said, leave the boiler alone – and use the thermostat to control the temp. If I want no heat, just knock down the target temperature.

I’m confused and tired 🙁

e maens make big changes on the thermostats, try altering by one degree to find how low you can go and still be comfortable.

Wrecker – like that – so many people have theories etc as to how best to control and this is the right way etc, but the best way is monitor and be practicable about it.

if you have a pump to remove the ‘waste water’ ( condensate from a combi boiler) and it is running all night it is not working correctly.

the pump should only run when the ‘tank’ is full ( circa 3-5 litres and then only until the tank is cleared circa couple of minutes.

even on max your boiler is only going to generate 2 litres an hour at the outside, most often barely an egg cup.

so if your pump is on all night when presumably the heating is off as your tucked under the duvet then i’ d be making a phone call.

cheers totalshell – just called them, they agree – and are sending someone out.

Thanks

wrecker – my tutor is working on a funded PHd around supermarket design and energy use.

Interesting. As a company we have been working for a major supermarket for a few years now on their energy conservation project. Existing stores so not getting involved with design. From a practical point if view, they could reduced their consumption massively by doing three things;
1) Put doors on the chillers (why they don’t do this is beyond me)
2) get proper decent maintenance. Some of the things we see are honestly gobsmacking.
2) don’t leave the ******* doors open. Retail must be one of the most wasteful industries; doors wide open, heating or AC on full pelt.

Oh, and did you know why they had to remove the turbine at emersons green? That’s a good one.

Problem there is that the thermostat is in the hallway. We don’t live in the hallway. We live either in the living room or bedrooms depending on the time of day

Can you get individual thermostats for each room? I know you can get moveable ones but that won’t work well with TRVs.. or will it? Hmm…

All we use to do was set the hall located thermostat to 15c (left all year) and then only move it to 19/20c when we were cold. We then turned the individual rad valves down to a level for the specific room.

Your temp setting will probably be different to ours, but you kinda get the drift.

2) get proper decent maintenance. Some of the things we see are honestly gobsmacking.

Because that’s OPEX not CAPEX… 😳

You have to be careful with quoted efficiencies, they put the boundary around the boiler. It can be quite a different matter when considering the house as a whole. A colleague had an old low efficiency cast iron boiler but it was situated in the middle of the house with the flue travelling from the boiler downstairs through the house (inc an airing cupboard) to exit at roof level. The boiler may have been inefficient but the system wasn’t. Heat lost from the boiler case warmed the house anyway and the flue gas gave up a lot of its heat as it travelled on its way out.

Problem there is that the thermostat is in the hallway. We don’t live in the hallway. We live either in the living room or bedrooms depending on the time of day

Can you get individual thermostats for each room? I know you can get moveable ones but that won’t work well with TRVs.. or will it? Hmm…

This comes back to the original design of your heating system, you have radiators calculated to heat a specific size of room, this calculation is based on various aspects, size, construction, proportion of outside walls, direction outside walls face, etc, etc.

Your heaing is controlled by the controller in conjunction with a calculated radiator. The other rads in the house with TRV’s allow you to easily vary the temperature in the room to aid your comfort. Some rooms you may want warmer, some you may want cooler that is my understanding of what TRV’s are for.

The more I read, the more I think it was an error moving somewhere with a communal woodchip boiler. Well insulated house, but I think less flexible in that I can only control the call off of hot water, and I bet there is significant heat loss between me and the communal boiler.

This comes back to the original design of your heating system, you have radiators calculated to heat a specific size of room, this calculation is based on various aspects, size, construction, proportion of outside walls, direction outside walls face, etc, etc.

Either that or they just made them the width of the windows!

Oh, and did you know why they had to remove the turbine at emersons green?

Yes. Saw the design problem on a website and thought ‘I know one that looks like that’. My tutor’s work is:

a PhD in Environmental Engineering at Manchester University, looking at and modelling the energy use of a supermarket, and how this may be brought to the zero required for all new build commercial buildings by 2019. She has been working as a Research Associate to Geoff Levermore on a Zero Energy Store project, within the Sustainable Consumption Institute, at Manchester.

I bet there is significant heat loss between me and the communal boiler.

Probably far less than you think. Insulating a pipe is a pretty easy thing to do and district heating is far more efficient than anything else. Most other Northern European countries have far more of it than we do. The UK construction industry is backwards on many aspects (backed up with the planning regs etc).

Probably far less than you think. Insulating a pipe is a pretty easy thing to do and district heating is far more efficient than anything else. Most other Northern European countries have far more of it than we do. The UK construction industry is backwards on many aspects (backed up with the planning regs etc).

It certainly makes me feel better knowing the plantation and saw mill next door is supplying the fuel to heat my house. What a guardian reader I am.

Great info on this thread.

Here’s a question for the experts:

There seems to be a secondary circuit for the central heating of the extension part of the house we moved into recently.
This means that when the wall thermstat in the living room is off the rads in the original part of the house turn off as you’d expect.
However, the extension part, which has three radiators, still stay on and the boiler continues to heat to its set temprature (68 c).
There is a secondary control valve for this circuit in the airing cupboard. There is no other thermostat in the extension.

Does this mean the only way to control the extension part is by adjusting individual rads in the extension?
And does that mean the boiler keeps heating to its set temp regardless?

Any help is appreciated!

Tootall, has he gone down the route of tri generation w/absorption refrigeration packs and CHP? I’d be interested to know his refrigeration “solution”
Feefoo, I *think* that the extension can’t be a classic secondary circuit as such as the primary must have temp to provide. It’s likely to be a seperate circuit, which you should be able to control at the boiler end. I’m not replying as an expert, others here would be better qualified to provide a more accurate answer.

If you put trvs on those 3 rads they’d shut down when at the required temp. If the boiler is relatively modern it should modulate right down as the return water temp would be high.

Cheers, wrecker, daveh, that’s what I was hoping. Boiler is only one year old so hopefully will modulate as you say.

FeeFoo – put a wireless programmable room thermostat on them, best way and you should have one to comply with building regs.

Bain – wouuld like to see that install if I am ever in your part of the country wherever that maybe. I assume you don’t pay for your heating, as it sounds like a commercial RHI project therefore someone is receiving money to burn fuel.

@Bear – it’s residential. Community wood chip boiler serving (I think) 22 homes. The boiler came from Wood Energy Ltd. I’ve not seen it yet so not sure of spec, but I’ve seen the tractor trailer bring the wood chip from down the road.

Each house has 2 hot water inputs, one goes to a tank with optional immersion heater, the other into the central heating. There is some sort of regulator/actuator that means the input pipes don’t pull hot water unless called by the system in the house, i.e you don’t have hot water constantly being pumped to the house and being wasted because not needed.

There is a flow meter on the input pipe which drives the billing arrangements. Not had a bill yet so may end up cursing the system. I’m not sure if the meter reads both flow and temp to derive some sort of combined energy transfer value, or whether it is just based on the volume of hot water. I suspect that you are right that the provider is making a turn on both the householders and some sort of subsidy arrangement, but as long as it works out cheaper than oil fired or calor gas it will make sense given the rural location.

It qualifies for commercial RHI because of heating more than one home, someone is making a fortune off your heating!

Where abouts is it, love to see it.