Knock on effective of balancing radiators

Thermostats, Volumisers, Buffer Tanks, TRVs, Pumps, Piping, Valves, Radiators & Controls

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Bash

(@bash)

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Topic starter 23/02/2026 9:15 am

Or HP was installed a few weeks ago and is running really well, the installation was spot on.

Our installers will be coming back to balance the radiators and I am trying to get my head around as to the best approach.

We have 11 radiators, all designed for 21c and are sized correctly.

The house is warm and comfortable, although the bedrooms run a little warmer than the downstairs.

I'd like to push more heat downstairs and take some from upstairs to get a better balance of heat that'd we'd prefer.

I know how to balance them through the LSVs, but I'd like to understand the if I can achieve the heat balance I'd like, if this is possible and the knock on effect on the system as a whole.

We have good volume, probably about 130-140 litres.

The installers (who are great) suggested using the bedroom TRVs to controle the bedroom temperatures. We only have TRVs in the bedrooms.

Is it better to use the LSVs to reduce the flow or let the TRVs do this?

I am conscious that if the TRVs close we lose that volume from the system.

Is it better to have less flow permanently by closing off the LSVs a bit and what is the consequence of this on the system as a whole?

We have an 8kw Daikin Monobloc, which requires about 50l minimum volume. We also have a 25l volumiser.

I know balancing is a very important part of a HP install and I don't want to make it worse chasing the best comfort at the expense of the whole system!

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JamesPa

(@jamespa)

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23/02/2026 9:56 am

Posted by: @bash

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Is it better to use the LSVs to reduce the flow or let the TRVs do this?

In a word yes, its better to use LSVs, for the reasons you clearly understand. Low flow continuously keeps max engaged volume and lowest necessary flow temp. Its also generally more comfortable! I found it pretty easy (and ultimately much more comfortable) to adjust the LSVs on my bedroom rads to achieve a comfortable sleeping temp whilst maintaining a higher temp elsewhere.

However you dont have to obsess about this if it doesn't suit your lifestyle provided the majority are on LSVs- I have one exception where I use a TRV, namely a room we use principally for guests. As a courtesy to the guest the LSV is fairly high, and they can use the TRV to turn it down.

There is an article on balancing here. Its important not to turn down all the LSVs, at least one (normally the rad that heats up slowest) should be fully open, otherwise you are unnecessarily restricting flow.

This post was modified 1 hour ago by JamesPa

4kW peak of solar PV since 2011; EV and a 1930s house which has been partially renovated to improve its efficiency. 7kW Vaillant heat pump.

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Bash

(@bash)

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Posts: 144

Topic starter 23/02/2026 10:23 am

Thanks @jamespa

Yes, I'd be leaving several radiators fully open with no TRVs (all the downstairs ones) and 2 bathrooms as want the most heat in these.

I'm assuming it's best to start with the bedroom closest to the incoming flow, turn that down and once happy, leave it for a day and then do the next radiator upstairs, i.e one at a time?

I'm assuming also that reducing the LSV flow in the bedrooms should push more to the furthest radiator (which incidentally is the one I want the most heat into)?

This post was modified 59 minutes ago by Bash

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