Live in a modern (5 yrs old) townhouse. (Lets call ground floor level 1).
Level 1 is freezing cold especially in winter. I foolishly tiled all throughout L1 on to conctrete without putting in underfloor heating but it's too late to do anything about that now. I have double sized patio doors & windows off the kitchen that I feel let a lot of heat escape due to their size. They are only covered (at night) by thin linen curtains. I have an integral garage though I have insulated and draught proofed the garage door.
Thermostat is on level 2. Levels 2-4 are absolutely fine temperature wise.
Every radiator has a TRV. Combi boiler on Level 3.
What is the problem?
Is it the thermostat on L2? If so is it a big job to relocate downstairs?
Is it just lack of covering on L1 windows? If so then I can sort that no probs obviously.
Will turning off the TRVs on Levels 2-4 and putting L1 on high work? Or will that eventually lead to the same problem just slower to heat the whole house?
A small point - L1 downstairs toilet is really toasty when heating is on as it's only a small enclosed area. This leads me to think it may be the back windows and doors (virtually a wall of glass).
I just visited a property with 24 rads that was cold!
The upstairs was hot and downstairs was cold. The answer is to balance the system.
All the heat is going up to L4, L3, L2 and not L1. If the boiler was on L1 the heating problem probably wouldn't be as bad.
Anyway, you have to force the heating water from the boiler down to L1 and to do this we balance the system.
The heating water will naturally rise to the upper levels but will resist the urge to go down to L1 - call it lazy if you will.
If you can, start with a cold system.
Start by turning off the plumbers valve on all rads on levels 4,3,2 and open the plumbers valves fully on L1. You may set the TRV's on L1 to a high number if you wish. You need maximum flow on L1.
Turn the heating on with room stat on maximum - to keep the boiler firing continuous while you are working. All rads on the upper levels should remain cold and L1 rads should heat up.
Set all other TRV's to L4 to number 3, L3 to 4 and L2 to 5.
Now crack open the plumbers valves on L4 and I mean a crack - just so the heat starts to creep through slowly. Do the same on L3 - it may be a quarter of a turn but that's all. On L2 do the same but these may need a half turn to allow a bit more flow through the rad.
This is the basic principle to balance the system. The higher you go, the slower the flow.
Any adjustments should be very slight and once set, the plumbers valves (lockshield valves) should not be touched again.
When the heating comes on again, the restrictions you placed by balancing the system should allow the house to heat up from L1 instead of L2 upwards.
Allow yourself a good hour or so to do this and take your time. If a rad doesn't heat up, don't be tempted to open the valve fully.