What heating controls should I have?As a minimum you should have a programmer (for controlling the times when you want heating)

  • a wall thermostat (to sense the temperature and send a signal to the boiler to either provide heat or to turn heat off )
  • thermostatic valves on each of the radiators to control the temperature in each room
  • a thermostat setting on the boiler controlling the temperature of the water that goes to each radiator.

It is good practice for new build homes to have at least two heating zones, each zone should have a separate timer and wall thermostat. For example you could have the bedrooms in a separate zone from the lounge which is heated at different times.

You should have thermostatic radiator valves (TRVs) on all radiators but not in the same area as a wall thermostat, it is possible that this room  may never get warm enough to turn the boiler off via the wall thermostat  if  the temperature in this area is being controlled independently by a  TRV.

Also, some boilers need at least one radiator without a TRV or a bypass in the system to ensure a minimum flow of water trough the boiler. In some boilers the bypass is within the boiler unit so please check if you need a bypass with an engineer.

If you have a hot water cylinder this should have a set point control thermostat installed so that the boiler will know when the hot water is hot enough to avoid scalding anybody using the taps.

What are heating zones and how many should I have?
Heating zones allow you to set different heating patterns in different parts of the house.

Each zone has its own wall thermostat and timer. For example  2 zones, 1 for bedrooms and 1 for living room, you can heat the bedrooms first thing and again before bedtime, while the living rooms warm up later in the morning and earlier in the evening.

Zoned heating can be installed by organising the plumbing with a separate radiator circuit for each zone or electronically using radiator valve actuators which are turned on and off from a controller

I don't have a wall thermostat - do i need one?
If you don't have a wall thermostat you must be relying on the boiler thermostat; this measures the return temperature of the water as it comes back from the radiators.

If you have fitted thermostatic radiator valves and adjusted them to your needs, then when the rooms are warm enough the circulating water bypasses the radiators and returns to the boiler almost as hot as it started, though it will also be losing heat from the pipes in the circuit between the radiators and this loss can be substantial - in most cases these pipes aren't lagged. If the heat loss is small the boiler will notice this and shut off. However, even then it needs to keep checking, so it periodically sends water round the pipes to see if heating is needed. If you have a room thermostat, this will turn the boiler off completely and will make at least some savings.

If you don't have thermostatic radiator valves and your rooms are warmer than you need then a room thermostat will help a lot.

Is it easy to add a timer or a control thermostat to my existing heating system ?
It depends on whether or not you already have a boiler which allows a timer to be integrated into the controls to turn the boiler off when heat is not required, you will need this facility in the boiler panel to install a controller or room thermostat.

Is it worth having radiator thermostats?
Thermostatic Radiator Valves (TRVs)] allow you to keep some parts of your house warmer than others. You can adjust them through the day according to need, or you can leave them on one setting most of the time.

For example if you have a spare room you don't use you can turn the thermostat right down except when you have a guest coming to stay. You might keep your bedrooms cooler than your living room, or turn them off during the day and only turn them on shortly before bedtime. You will need to keep doors closed as well to stop heat leaking in from other parts of the house. How much you save with TRVs depends on how much of your house you can reduce the heating in.

How should I set my radiator thermostats?
Setting your radiator thermostats can be tricky because any temperature change in a room takes time and you don't get a click when the radiator valve opens or closes.

For most rooms you will need to experiment by making sure the heating is on first. Then go into each room and see if it is too warm or too cool: tweak the radiator valves up or down accordingly. If you have turned the heating up, check in a few minutes to see if the pipes are warm showing that there is hot water coming in. If not, tweak some more. If you have turned the heating down then the pipes will cool but this will take some time. Check the room temperature again after half an hour (making sure the heating is still on) and tweak some more as necessary.

Can I get a thermostat that sets different temperatures for different times of the day and week?
Many modern programmable thermostats can do this. You can set different temperatures for different time windows during the day. For example you could have different settings for getting up in the morning, early evening and late evening.

What is the best position to fit my radiators?
You want air to be able to circulate in front and behind your radiators and then into the room, it is usual practice to position the radiators underneath a window to avoid cold spots in the room.

  • If you have long curtains do not allow them to hang in front of the radiator as you will not get a free flow of warm air through the radiators into the room.
  • If radiators are on an outside wall you could put a reflector panel behind them which will help not to lose lots of heat through the wall. This is especially the case if you have solid walls.
  • If the radiators are positioned behind furniture the free air will not circulate freely and warming furniture before the room is not an efficient way of eventually heating your room.

What is the best position for my wall thermostat?
A wall thermostat is best fitted on an internal wall, maybe a hall way, and away from direct heat sources including radiators and also electrical equipment such as TVs or computer monitors.

It is usual to put thermostats at about head level. If you put them lower then you should set the temperature a little lower than you would have done because the air is usually cooler at lower levels (especially in draughty houses).

You should not have a TRV on any radiators in the room with the wall thermostat, If you do then it is possible for the TRV to shut down the radiator before the thermostat shuts off the boiler, so the room never gets hot enough to trip the wall thermostat and you will find the boiler runs all the time whether you need heat or not.

For rooms I rarely use, should I turn the heating off completely or keep them a bit warm?
Even if you turn the radiators off and close the door some heat will transfer through from the rest of the house and you may find this is enough to keep the pipes in the room from freezing.

However it may feel a little damp after a while, so keeping the valve at the frost protection setting and regularly ventilating the room would be the recommended minimum .

When I am away in the winter, how should I set my heating to stop the pipes freezing?
7 C is probably warm enough but you would need this on all the time, through the night as well as during the day.

At what temperature should I set the boiler thermostat?
The boiler thermostat sets the temperature of the water that circulates through the radiators. This obviously must be warmer than the room temperature you want to achieve and the hotter the radiators the quicker the rooms will heat up.

However, be aware that if the radiators are too hot people can burn themselves.

Each system is designed differently and condensing boiler manufacturers recommend that systems are normally balanced to give you a 20C temperature drop from 70 oC flow down to 50 oC return.

That means the boiler thermostat is set to 70 oC and the water returning from the radiators back to the boiler is 50 oC which is low enough to give good condensation and maximum efficiency.

If you have a non-condensing boiler, it is normal to run the flow at 80C with a drop of 10C through the radiators, so the return temperature is 70C.

If you have a hot water storage tank it should maintain the domestic hot water for baths and basin taps at 60 oC to avoid growth of dangerous bacteria such as legionaires disease.

Your boiler probably has a separate control setting dial for the hot water heating circuit and this needs to run no more than 60 oC and no less than 50 oC, either way system mixing taps are recommended fitted prior to draw off to avoid scalding.

I have a solar panel for hot water - what difference does this make?
To get the most energy from your solar panel you will need to time the water heating so that it tops up the heat in the water tank only when necessary and by only as much as is necessary.

You should time this to heat up the water just before you use it, or at least after the sun has done as much as it can. For example, if you mainly use hot water in the morning 7-9am then you could top up the tank in the morning around 6am so there is enough when you need it. During the day the sun will give you free heat but if this is not enough the boiler will supply the difference the next morning.

Problems
I am cold and the radiator in here is cold - what should I do?
Check the thermostatic valves on the radiators are turned up, the room thermostat is turned up, the time controller is on , the boiler is on and the system is up to pressure ( if applicable). Otherwise, if the radiator is partially warm, check for air in the system . If the radiator has a TRV try turning it up. If that doesn't help it may be stuck.

I am warm so why is the boiler still on?
Is it heating the radiators or only the hot water? If it is running heat through the radiators, check the room thermostat and consider turning it down.

My radiator has a TRV but it is always on (or always off)
Radiator valves can sometimes stick. Try turning it right down, then up, then back to where it was. If it is still stuck you can try removing the head of the valve and fiddling with the pin to free it up - try alternately pressing and releasing it but if it is totally stuck then you may need a new valve which means draining the system.

How can I warm the house up more quickly?
Adjusting the thermostat won't help - this is either off or on. You can adjust the boiler to increase the temperature of the water circulating round the radiators.

It takes a lot of energy to warm up this house - won't I save by leaving the heat on all the time?
For most people it is much better to let the house go cold when you don't need the warmth. When the house is warm it loses more heat than when it is cold so if it is warmer than it needs to be it is losing more heat too.

If your house is taking a long time to heat up it could be because you are experiencing a lot of heat loss through draughts and poor insulation.

Stopping draughts and improving your insulation will reduce this. However, your house may take a long time to heat simply because it stores heat in the walls and floors - this can be a good thing as it will also stay cooler for longer in summer.

My radiators aren't warming up evenly. What is wrong?
If the radiator is cold at the top and cold at the bottom it probably has air in it ( please see "How to bleed a radiator"). You will need a radiator bleeding key to open a small manual valve at the top of the radiator to let the air out. When air passes and water appears you must close the valve. It’s a good idea to have a tissue or a cloth to catch mop up.

If the radiator is cold in patches then it may be blocked up with sludge or scale. It needs to be flushed through with descaler to clean it out.

NB. Every time the radiator system is refilled a chemical inhibitor should be added to prevent scale.