Using some or all the radiators - does it make much difference?

DreamerV

Hi,

I was wondering if not heating 2 of the rooms in the house which aren't used, saves money on the gas. I know with water, you pay to heat it, even if you don't end up using it, so wondered if it's similar with gas i.e. by putting on the heating system, you pay no matter how you distribute that heat between the heaters. If it's better to leave those 2 rooms (1 radiator in each) unheated, then should I be closing the door to each to keep the cold out of the main part of the house? Also does turning the thermostat down on some radiators while at 18 on the main thermostat make a difference to costs?

Thanks

Possetjohn

If the radiators in two rooms are shut off and the doors to those rooms closed then you should use less gas as you are heating less of the air volume in the house. The amount of gas saved will depend of the type of boiler (how modern) and the insulation in the house. You will still get some heat leakage into the closed rooms. From your second question I assume you have thermostatic valves so it might be worthwhile just setting this on a low setting or even the frost protection setting (*) to minimise dampness in these rooms. As the coldest place in the house it will be where any warm moist air getting into the rooms can cause condensation so open windows when the conditions are suitable.

The thermostatic valves on the radiator will close the flow of hot water to the radiator when the room temperature is higher that the valve set temperature. They work in a progressive way reducing the water flow as the room warms up and if the setting is lower then the temperature the room is heated to is lower and you will use less gas! When the main stat reaches its set temperature it turns off the boiler and will not turn it on again until it drops below the set temperature. The span depends on the thermostat type. Modern electronic types are +/- 0.5°C while the older bi-metallic type can be +/- 1 or more °C

As a general rule the less you heat the house the more gas you will save. It is a question of your tolerance levels!!

If you search this board there are many discussions on this type of topic

rogerblack

The boiler will be marginally more efficient when running all the boilers together.
However, in poorly insulated houses, you can considerably reduce the amount of heating needed by only heating part of the house, so the minor efficiency loss of the boiler can be swamped.

In general - the more you have colder for longer, the less gas you use, it's quite simple!

However! Pick two days that are going to be similar in temperature and wind. Do it one way in one day, one way the other, and measure. It may make a big difference, or it may not be worthwhile.

DreamerV

Thanks both, much appreciated. I did a search but I obviously typed in the wrong things (my issue, will try and improve my search skills!) My house is meant to be well insulated, but I find it loses heat quickly and takes a long time to heat up. I'll shut the room doors and leave the heating off there, and turn the heaters in the rooms I use less frequently (kitchen, hallway) down low. I'll test it on 2 separate occassions for a similar couple of days each time. One of the 2 rooms I mentioned has a thermostatic valve, the other has a valve that turns but has no markings on it at all, but I assume does the same.

I'll get to the bottom of this being efficient malarkey in time

bengasman

rogerblack wrote: »

The boiler will be marginally more efficient when running all the boilers together.

That remains to be seen.

rogerblack wrote: »

However! Pick two days that are going to be similar in temperature and wind. Do it one way in one day, one way the other, and measure. It may make a big difference, or it may not be worthwhile.

This method is totally unreliable to gauge the difference.

rogerblack

bengasman wrote: »

That remains to be seen.


This method is totally unreliable to gauge the difference.

Marginally less - a small amount.

There are fixed losses - pumping, ... - and the loop temp will likely rise, perhaps a lot with a boiler that won't modulate down (enough), reducing efficiency a little.

Comparing two similar days is somewhat inaccurate, for best accuracy you would need to for example, for 8 days compare the two strategies on odd and even days, and add up the totals for each method.

In a well insulated house, the amount you can save by this method is relatively small, simply as the insulation between rooms is very poor compared to that to the outside, so heat passes to unheated rooms quite readily through the internal walls.