Smart valves to save money?

[Sitchey]

Hi

I'm looking some advice on the best heating setup for an existing system that would reduce wastage and save money.

Current setup
I have an oil fired system with two Nest thermostat zones (one upstairs, one downstairs which also heats water). The thermostats are in separate rooms (Hall and bedroom) and give me two zones. Each zone has 14 radiators (a mix of singles, doubles and towel rails).

At present when I turn the heat on we heat all the radiators in each zone. We do manually turn some off as some rooms aren't in use. But we don't this for too long as still want to avoid damp.

I want to install smart valves to better control the temperature in each room, and shut of (and on) some rooms that aren't used much.

My question
I'm installing the valves to save oil and money. But my question is, will controlling the valves and turning some rooms off do this? Or will because the thermostat set the temperature eg 23 degrees, mean that they keep the boiler going more as it will take longer to heat up the zone with less radiators on.

Thanks for any input

 

[Brambles]

Smart valves control each room as an individual zone, assuming all the radiators and towel rails are connected with smart devices, you don’t have a central thermostat. If required you only heat one room - with each room on its own preprogrammed settings.

For a 28 radiator system and DHW, you are probably looking at £1400 to £1700 for the equipment ( 28 smart valves @£40, DHW controller £100, control unit £250 - you may need 2 control units depending on the number of zones you want to create). With a large property make sure that you have connectivity for all the devices you are going to connect. Very few of the available systems have wireless repeaters

I would do the sums - if all the rooms in the house are in use of some sort every day, the payback period for savings on fuel will probably be in excess of 10 years.

Generally, money spent on the elimination of damp, draught proofing and insulation pays better dividends.

 

[Sitchey]

Thanks for the reply.

So if each room has an independent valve it will override the main thermostat and keep calling for heat until it reaches its own set temperature?

As Nest doesn't have a valve, I've went for the Netatmo ones. It all syncs to my home kit and is controlled by Alexia. I have a relay in the Hall and tested that it reaches around the house ok. The only issue is that each relay can only control 20 valves, so will need another one to do all the radiators.

So far I have 5 of the valves set up as a test. Seems OK so far, but need to setup up proper schedules as sp easy to forgot that when u turn on the heat it doesn't mean that a room with the smart valve will heat.

In terms on a return I'm not too concerned on how long it takes or paying it back. More so that it starts reducing oil consumption

 

[Brambles]

In essence smart radiator controls are a small step up on traditional wax thermostatic valves. From a fuel saving perspective the difference is probably quite small. What smart controls do do is to allow a better more comfortable distribution of heat in large properties where not every room is used every day.

If all the rooms are controlled by Smart devices you do not have a “main thermostat” and you don’t really need a zone valve, unless you have a system that tends to gravity flow in the summer

If the system it is only partially smart, how are you controlling the existing zone valve? The smart controls will only function if the zone valve is open - if it is open it will feed the other non smart emitters at the same time. That defeats the objective you are trying to achieve.

To reduce oil consumption reduce the boiler flow temperature, to maximise the duration that the boiler condenses. That of course assumes that you have a condensing boiler. You can monitor condensing performance by measuring the boiler return temperature.

Thereafter reduce the room temperatures and durations that they are heated. You will probably need to make dramatic changes to see any fuel cost savings in real terms.

In simple terms, the difference in the cost of energy between the maximum room temperature in a house of 18 degrees and 21 degrees is between 25 and 30%.

 

[SimonG]

Turn the room stat down a degree or two. Swap out light bulbs for LEDs. Increase insulation where you can.

Big expense on the smart trvs. Long payback.

 

[SJB060685]

@Brambles advice is sound advice and to be honest they know more about these control systems than I do so I can’t add to that.
Your house and system is obviously large based on your description. If you really want to cut down on fuel in the long run then I would suggest considering major improvements to insulation levels in the property first and then reconsidering your heating system.