What's the best way to run my central heating?

[Tumble]

Back in my old house, I had a thermostat, mechanical timer and standard rads. In this place, I have a combi boiler, master thermostat and thermo rad valves on all the rads in the house. Am I better off having the heating ON all the time and letting the rad valves and the master thermostat sort it out, or setting a 2 period timer for each day?

[Ferral]

We had a new boiler installed earlier this year and a technician came out and went over it with us.

First off set your radiator temperature to around 2 thirds instead of full, this makes it more energy efficient.

If your boiler has a pre heat turn it off as that just wastes gas keeping water at a certain temperature even when it is not in use.

We usually have the thermostat set to 20.5 Celsius for day and night, just a nice living temperature.

We have the valves on all radiators fully open presently as it is getting colder, if it gets a bit warm we knock the thermostat down a few degrees to knock the heating off and we control the room temp by adjusting the radiator valves.

Overnight we tend to knock the thermostat down to around 17 degrees, this way the boiler won't be firing constantly during the night running up larger gas bills. Another reason for this is that it can end up getting overly warm on a night if the thermostat is fighting the drop in temp, thing is though you are snuggled up in bed so won't particularly benefit from the heating being on overnight.

Once the thermostat hits the day cycle usually at around 8am it returns itself to 20.5 degrees and the heating fires up warming the house just nice for while you are having breakfast etc

[peterb]

Thermostatic radators are great for maintaining the temperature during the day, but they need to be set lower than the master thermostat, otherwise that will over-ride them all. At night, you probably want a lower temperature, so you could turn down the master thermostat so that it controls the heating, or just turn off the heating at night, using the programmer.

I leave heating on constantly, but I have a programmable thermostat that is set to different temperatures throughout the day, with a lower temperature at night. No thermostatic radiator valves though. The boiler then fires according to the thermostat setting at the appropriate time of day.

[Zak33]

mine is on 6:30 am to 7:45 am... and 3:30pm to 8pm

Main hall way thermostat is at 18most of the time when we home, 15 when we leave house, 20 with guests

radiator valves are all set relevant to room temp reqiure... living room has 2 rads, both v powerful both set low... dining room one small one.. set to max


Boiler set to the letter E for economy

[Harnser]

I'm in a similar situation to the OP, though without a combi boiler sadly (first house in 15 years with a hot water tank - have noticed the increase in electricity bills!).

How do thermostatic radiator valves trigger the boiler not to run, unless the radiator valve knows it needs hot water? Or am I totally misunderstanding how they work?

I thought it meant each radiator had a bypass hot water pipe, so a radiator could be on or off, and all the other radiators could still receive hot water (like a wire next to a resistor, and a switch to choose between them). As I've never spotted a bypass pipe, I think this is wrong. But then how does one radiator off not stop all others from getting hot water?

[Zak33]

and.,.. CONGRATULATIONS

[peterb]

I'm in a similar situation to the OP, though without a combi boiler sadly (first house in 15 years with a hot water tank - have noticed the increase in electricity bills!).

How do thermostatic radiator valves trigger the boiler not to run, unless the radiator valve knows it needs hot water? Or am I totally misunderstanding how they work?

I thought it meant each radiator had a bypass hot water pipe, so a radiator could be on or off, and all the other radiators could still receive hot water (like a wire next to a resistor, and a switch to choose between them). As I've never spotted a bypass pipe, I think this is wrong. But then how does one radiator off not stop all others from getting hot water?

The radiators are connected in parallel, the lock shield valve should regulate the flow so that with all the thermostatic valves open, the flow is roughly the same through each one, although in practice that rarely happens.

The boiler fires when the return eater temperature is below the set thermostat temperature (the boiler thermostat, not the room thermostat) and that happens when the radiators are cooling the water because the valves are open

The room thermostat shuts the boiler off when the room it is in gets up to the same temperature.

Ideally the heating system should be in zones, with a room thermostat for each zone,. One zone might be upstairs or a sleeping area, which might be a off during the day, but on a low temperature at night. Living areas are the opposite. Again that is rarely realised in most homes.

A programmable thermostat sets different room temperatures for different times of the day, depending on occupancy, but may have a minimum maintained temperature so the house heats up quicker as the temperature doesn't drop too low.

[Harnser]

Thank you peterb for that excellent response! I like the idea of zones - I know what to aim for when I finally buy a house.

[Lucio]

We've managed to get our gas bill to half the standard for a couple (according to the gas company) by leaving the heating off when we're out the house, and set to come on 30 minutes before we're due home, thermostat set to 22 (below that it doesn't come on)

Makes a nightly trip to the loo a bit chilly, but most of the time the people in the flat below us can be relied on to heat our floors.

[scaryjim]

Been a long time since I lived in a house with a useable room stat, sadly - when we did we had a digital one that kept the living room at a constant 17c and barely ran the boiler at all, it was great

I think with TRVs - as peterb eluded to - you're better off having the master themostat relatively high and then letting the rad valves deal with the managing each room. We genreally keep the rad valves down in the 1 - 3 range, and have timed heating for a couple of hours in the morning and then throughout the evening until bedtime (stupid, poorly-insulated, draughty rented house struggles to hold heat). If we're in during the day (generally at weekends) we'll swich from "timed" to "on", hopefully remembering to drop it back to timed before bed

[Moby-Dick]

programable thermostat helps - we didn't go as far as getting a nest , but we where able to get one that connects to our solar/electricity monitoring solution. Seems to behave itself pretty well and only having a "comfort" and away button on the box stops the Mrs from turning it up to volcanic temperatures

[Spud1]

I have a very similar setup at the moment - but with a programmable thermostat so I can set the temp low when I am at work. I typically have the boiler always on at 2/3rds power, with the temp set for 19 degrees when I am in the house, and manually boost it if I feel I need it. This seems the most efficient for me, but I am in a newbuild house thats very energy efficient, so the heat is typically well retained. My biggest problem is the thermostat location, and imo that will have a bigger effect on how efficient your hearing will be than if you have your boiler always on or not. I can often find that my lounge is noticeably cold, but the thermostat still says 19 degrees.

At the moment I am attempting to solve that problem by upgrading my setup to be all z-wave, running off a rasberry pi (using a Razberry board). This will entail replacing the main thermostat + relay with a z-wave one, adding a room stat for each "zone" and swapping out the TRVs for z-wave. Out of the box you then have a system exactly like Hive, but its very extensible and has some nice APIs (including a web service one) so you can add your own features. I'm adding geofencing for example by using a simple Tasker script to call a web service.

Cost wise upgrading to z-wave comes in at around the same price as hive/nest/etc if you buy the parts from the UK - but by taking advantage of Alibaba you can get the TRVs for around £10 each and room sensors for £20 (from reputable places - much less from the more sketchy sellers!) making it around £200 all in. Only things I am buying from the UK are the z-wave controller board and the boiler relay..i.e. the critical bits! Worth a look if you are after a project

[wasabi]

No thermostats here, just use the timer. According to the e-on bill comparison thing we're at around half the typical usage for a property our size. Although no kids in a 3 bed semi and we both work, so not sure how useful that stat is.

[scaryjim]

... My biggest problem is the thermostat location ...

In systems run primarily off a room stat, this can be an absolute killer. We once had a room stat system where the stat was in ..... the kitchen. The very small kitchen. Which didn't have a radiator in it.

Most of the time the heating was on because the kitchen was unheated so no matter how much heat got poured into the rest of the house the temp in there was very low. Until we started cooking, of course, because the kitchen was small and rapidly got very hot. In the end we didn't even look at the temperature on the 'stat - we just used it as a remote on-off switch for the boiler. It was completely incapable of functioning for its primary purpose - just because it had been put in the wrong room...

[DanceswithUnix]

I find it odd how people seem to try and "game" their heating systems

I finally got a plumber in to fit thermostatic radiator valves (TRVs) to the bedrooms, as clearly I was never going to get around to it myself. He charged £30 each for the 4 valves which includes his time for draining, refilling and bleeding the system so I think it was a fair deal. It has made a massive difference to the comfort of the house.

So, I have a modern electronic thermostat downstairs which I consider a must as the old analogue dials introduce hysteresis where the temperature goes between too warm to too cold all the time. Modern digital ones are predictive and learning, so can hold a rock steady temperature at the thermostat location.

But heat rises, and so hence the upstairs thermostatic valves. I can set the radiators in each bedroom to a pleasant temperature. If there is a really cold snap, then the radiators will come on just enough to keep the bedrooms OK, but generally those radiators are pretty much cold. That pushes all the heat from the boiler to downstairs radiators where it is needed. Ideally I would have TRVs downstairs as well, but I hoped it wouldn't be necessary and so far it seems OK.

So to re-cap:

I told each bedroom radiator thermostat how warm I want that bedroom.
I told the master thermostat how warm I want downstairs to be.
I leave the heating on all the time, 24/7, all year round.

In the summer the temperature is naturally higher than the thermostat setting, so still leaving the heating on all summer does nothing.

Todo? Well that digital thermostat is very programmable, before the bedroom TRVs were in I just left it in manual mode and set it to 21 degrees. Now I think I have enough control of the house that I need to dig out the instructions and tell it to drop the downstairs temperature to, say, 16 degrees while we are in bed. The cat might have to find a new spot to sleep, but otherwise hopefully we won't notice the change other than a drop in gas consumption.

I think most of our gas cost is in heating baths for the kids.

[DanceswithUnix]

In systems run primarily off a room stat, this can be an absolute killer. We once had a room stat system where the stat was in ..... the kitchen. The very small kitchen. Which didn't have a radiator in it.

Most of the time the heating was on because the kitchen was unheated so no matter how much heat got poured into the rest of the house the temp in there was very low. Until we started cooking, of course, because the kitchen was small and rapidly got very hot. In the end we didn't even look at the temperature on the 'stat - we just used it as a remote on-off switch for the boiler. It was completely incapable of functioning for its primary purpose - just because it had been put in the wrong room...

I notice you can get radio linked ones now, so you can have the 'stat in a different room to where the muppet that did such wiring originally put it.