Are heating controls essential to get the best use of a solar system?

One of the solar installers that quoted me for a new system informed me that it is essential to install heating controls to get the best use out of our solar system and the efficient boiler that we have already installed.

I previously came to the conclusion that our small terraced house is not the best candidate for zoning and heating controls. Our house is very well insulated and we don't have the problem where parts of the house are too warm or too cold.

At a cost of €1000 for the controls I can't see how I will get the return. If I can get the grant, it will reduce the cost by €400 I believe.

Is it worth it?

Heating controls is always of benefit, however, if you did not want the "full monty", you could fit a motorized valve wired to the cylinder thermostat. That way on good days, when the cylinder is hot, the valve will close, leaving a smaller circuit for the boiler to heat and the radiators will heat up quicker. It is considerable cheaper and will definitely save money on fuel.

It is not ideal but a decent compromise. Just remember it will not achieve boiler interlock and will not turn off the boiler.

A more important companion for solar is to make sure that you have a power shower or even a gravity fed shower installed instead of an electric shower, as it is no point in having a tank full of hot water and then having to heat it with a 9kW electric shower!

OkeyDokey said:

One of the solar installers that quoted me for a new system informed me that it is essential to install heating controls to get the best use out of our solar system and the efficient boiler that we have already installed.
...
At a cost of €1000 for the controls I can't see how I will get the return. If I can get the grant, it will reduce the cost by €400 I believe.

Is it worth it?

Click to expand...

If the solar panel has already heated the cylinder, then passing water through the coil won't have much effect on it. The only exception being if the solar has brought the water to 80C, then the central heating will harvest the difference between 60 and 80 and kick it into your radiators.

However, if the central heating heats the top half of the cylinder at 8.00 in the morning, it is going to deprive the panel of work. So it is worth zoning your cylinder, and only heating it at night in summer. You may opt to heat it day-and-night in the winter.

As regards zoning the rest of the house, that is a stand-alone issue, which can probably be met with TRVs. It won't improve the performance of solar either way.