Our gas bills were crazy, so during the summer we had the walls and loft insulated, and over the last couple of days we have been having a new boiler installed (with new thermostat & rad controls etc).

Our old 30+ year old boiler was around 55% efficient, so we are hoping to save money in the long run.

Is there a better way to keep house/water warmish? Do I put heating on for an hour here and there, or leave it on low all day?

It’s a condensing boiler if that makes any difference.

is it a combi boiler or normal boiler linked to a vented/unvented hot water tank?

They have taken the hot water tank out of the airing cupboard – so I think that makes it a combi?

99p pack of lighters from the 99p shop.

think of all that extra empty space from where they took out the old water tank you’ll now have to heat!

They have taken the hot water tank out of the airing cupboard

That will really piss Bear off now 😉

It’s a pity they did that.
Anyway, if theyve left you with a combi then all your hot water is created on demand – not stored, then used, so there’s not much you can do in that respect.

Assuming you have TRVs fitted to all your radiators, then its a case of sorting out the minimum comfort level you want for each room in the house.

do what the freehold owner (spelt w a n k e r ) had done in my first flat – connect his electricity supply to my meter …… luckily I did a test with everything off and started investigating

Assuming you have TRVs fitted to all your radiators, then its a case of sorting out the minimum comfort level you want for each room in the house.

Cheers – so just leave on all the time and adjust thermostat/controls accordingly?

It’s a pity they did that.

We had three different people round, and they all reckoned it was the best thing to do 🙁 I guess it’s better to have a tank then?

Depends on lots of things. Air tightness, thermal mass, type of house (detached etc) sometimes we heat buildings 24hrs over the heating season because it would take a huge amount of heat to bring back to temp due to thermal mass. Don’t do much with residential though sorry.
Try some different things for similar periods and record your gas meter readings. The calcs to convert the readings to kWh are available online. Perhaps do some degree days to normalise the data for more accuracy. There are some good resources for this online also.

Cheers wrecker – monitoring would probably be the best way…I’m pretty half soaked though so will keep forgetting!

Cheers – so just leave on all the time and adjust thermostat/controls accordingly?

If I wasnt in the house most of the day, and assuming your house isnt a barn of solid stone then Id say set the CH to come on sometime before you get home and off again at breakfast.

We work from home so have the heating set to 17degrees throughout the day, but a Underfloorheated stone floor works well for that.

Cheers,

Between us (wife works odd shifts as a nurse, and I work from home a couple of days per week) there is usually someone around. Think I’ll start by keeping it on low and monitoring.

Thanks all

BTW – if you log the gas meter reading each day, you can work out how much volume (and hence cost) each day is costing you.

Will do. I bet I can get an app for it!

Do you have a spreadsheet that could do that for me 😉

you have a graph of your won as well dont you

Do you have an electronic thermostat? We have one and the house is much more comfortable for more of the time and the heating bill hasn’t gone up.

Do you have an electronic thermostat?

I think so. I have in front of me a Honeywell CM927 7 day wireless programmable room thermostat with LoT technology.

Catchy.

Sorry to butt in. We’re moving into a solid stone house in a few weeks. Combi boiler, possibly with TRV’s, looking at getting a stove fitted too at somepoint in the future. With the thermal mass issue, would we be better off leaving the heating on all day then?

what about water?

leave it on all the time, or say 2 x 3 hrs / day

do you use more energy reheating it?

(bit of running battle with the wife this one!)

It’s a combi? It’s on demand.

bear had a go at me recently for doing the same

we are a couple in a 3bed – with 2 hot water taps and an electric shower

we decided to go combi and rip out all the extra tanks.

it depends on usage as we use that little that heating up a big tank of water all the time isnt great use.

ive got mine set to not let the house drop below 14 but generally it seems only to come on at 4am for an hour and the house is warm for me getitng up at 5.30.

at night i come home and stick the stove on and the boiler doesnt get a chance to fire up.

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

plumbers so far have gone for
1. 1 for 1 replacement of the system boiler, retaining the current tank
2. system boiler with new unvented tank
3. large combi, no tank
4. slightly smaller combi with some heat source gizmo to improve the hot water resilience, no tank

what’s the best way to go?

couple of days we have been having a new boiler installed (with new thermostat & rad controls etc).

also have been recommended to get an outside temperature sensor, keeps the boiler in condensing mode and therefore more efficient

“also have been recommended to get an outside temperature sensor, keeps the boiler in condensing mode and therefore more efficient “

i read about this – can someone please explain this to me in laymans terms.

FWIW my boiler lives outside if that makes any difference…..

“We’re moving into a solid stone house in a few weeks. Combi boiler, possibly with TRV’s, looking at getting a stove fitted too at somepoint in the future. With the thermal mass issue, would we be better off leaving the heating on all day then? “

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.

Honeywell CM927

I have two of these too.
Theyre very good.

Put it in the middle of the house where there is a radiator WITHOUT a TRV. Set your TRVs in the other rooms to their comfort level, and program the CM927 to aim for a particular temp at anything up to 6 periods during the day and for each day.

Mine is something like 5:30am to 9am @ 18deg, 9am to 3pm 17deg, 3pm to 11pm 18deg and then 16deg overnight.

what about water?

leave it on all the time, or say 2 x 3 hrs / day

do you use more energy reheating it?

with a combi you dont have it producing hotwater at various times – it just produces it on demand (i.e. when you open the tap) so there’s no setting for timings.

If you have a boiler and a hot water tank then that’s different – but TBH I dont have any experience of the most efficient way of setting the timings for that.

“with a combi you dont have it producing hotwater at various times – it just produces it on demand (i.e. when you open the tap) so there’s no setting for timings.”

depends on the model though stoner – ive got a small tank in mine that can be kept warm all the time or i can get a grant programmer that will only let it warm the water up at certain times.

fairynuff.

Im sure we’ll get the full going over on our course with the guys up the road at Worcester Bosch sometime. Maybe I can get Bear to guest lecture on Windhagers 🙂

Cheers Stoner – exactly the advice I was after

ta

Any heat which you put in will be transferred to cold surfaces before it makes much different to air temps. So if you have a large thermal mass ( think a big slab of concrete) you will need a large amount of heat to transfer to the mass before you’ll start warming the air in the building. Sometimes it’s better to retain heat in the slab rather than let it lose the heat to atmosphere. It’s a very difficult thing to calculate.

A very good use of an OAT sensor is to use it as a hold off for your heating circuit (providing you have a modulating boiler). Find the sweet spot of your building (the lowest temp where you do not need to heat the building to maintain comfort) and set it to hold the heating circuit off if it’s above that temp. Then it really doesn’t matter what your trvs are doing or who plays with them!

Hot water is a little different. You want the DHW system to hit 60 degc for at least an hour in every 24 ideally ( this is a commercial requirement only but not a bad one). Put it on a timer and lag any pipes you can!

You want the DHW system to hit 60 degc for at least an hour in every 24 ideally

What is the rationale for this because I at present pay to heat water in a house that it unoccupied in the week and would prefer to avoid this unnecessary cost if possible.

i believe its legionaires – thats why the hot water in the taps in our office seem to be set to 1 degree below scald.

With the thermal mass issue, would we be better off leaving the heating on all day then?

See, not convinced here. From a physics point of view, your house loses more heat when it’s warm (greater temperature differential) so it would make more sense that way to let it cool down overnight and when you’re out.

However, if you have weedy heaters (ie not many watts available) and a large heat capacity house (ie big stone barn) then you might struggle to bring the house up to temperature.

OTOH if oyu have a large heat capacity house then it’ll stay warm for longer too. This would allow you to turn the heat off earlier in the evening.

Our boiler only runs for a minute or two when it comes on. It’s actually more efficient to run it for longer afaik, so from this point of view letting your house cool down might also be good.

ive given up trying to find an answer for you molly

i came across this and im not sure if its real or a troll…..

http://www.thisismoney.co.uk/money/experts/article-2156438/How-I-house-warm-costs-down.html

the comments are commical – alot of them are heading for internal damp issues.

how ever if you dont have a programmable thermostat then your on a hiding to nothing.

Yep trail rat. L8 regs.
I’m only trying to help. Listen to molgrips if you want.

Another tip with a condensing boiler to increase efficiency is to use the coolest flow boiler flow temperature that you can.

Try setting the flow temperature to 50degC. This means that the heat exchanger tank is cooler and more flue gases condense on the tank reducing the amount of waste heat chucked out the flue.

If 50 degC doesn’t warm your house up enough then you need to increase the flow temperature. As a guide automated systems will automatically control the boiler flow temperature from around 40 degC when the outside temp is around 20 degC and increase it to 80 degC as the outside temps fall to freezing.

Some boilers allow you to buy a module that will automate this process. It’s call OAT compensation.

With the thermal mass issue, would we be better off leaving the heating on all day then?

See, not convinced here. From a physics point of view, your house loses more heat when it’s warm (greater temperature differential) so it would make more sense that way to let it cool down overnight and when you’re out.
Interesting this. I live somewhere where it’s about -20 outside overnight in winter, and it’s very much a case of leaving the heating on 24h with the thermostat – I tried turning off the heating one weekend that we went away, and it took 2 days to get the house (terraced, brick) back up to temperature.
But I’ve wondered whether letting it drop to, say, 12C during the day, then kick back in an hour before coming home would save any money.

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

ah yes real world experiance world rather than mathmatical physics world….

We tied that and found that the house temp never dropped below 17 degrees anyway, which must have meant we were well insulated.

I’m sure leaving the CH on all day is better but I’ve never been able to prove it for myself because we’ve always done it during cold snaps.

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.

Combis, pahhhhh……. horrible things (suit some situations) but are massively overused by the installers because they are easy to fit, five pipes in / out cash in pocket, scrap for copper cylinder thanks very much.

Have a look at the new Honeywell control system, but CM927 are good bits of kit, did a house very every individual room was controlled by one, was a very posh expensive job mind you!