I kept blaming the lounge. “It’s just a cold room.” It wasn’t. It was stealing most of the flow while the small bedrooms wheezed along behind it. I’d put off balancing because it sounded fussy. It wasn’t. One rainy Saturday, two clip-on thermometers, a screwdriver, done.
Set up took ten minutes. Bleed every radiator. Twist all thermostatic radiator valves (TRVs) to the same mark (I used 3). Drop boiler flow to 50 °C so you’re not chasing hot pipes. Find the lockshield on each rad (the little valve under the cap). The goal is simple: each radiator should have roughly the same temperature drop between flow and return, about ten degrees. Not perfect. Close enough.
Before I touched anything, I timed warm-up and noted a few temps. Kitchen hit hot in six minutes. Box room needed twenty-five to feel alive. Lounge drop across the rad was only three degrees, basically a bypass. Box room was sixteen, starved. Boiler short-cycled because one loud radiator told it the house was done.
I started closest to the boiler. Thermometer on the flow, another on the return. With the lockshield wide open, I read the drop, turned the valve a quarter, waited two or three minutes, read again. Quarter turns only. Water takes its time. When I got near ten degrees, I moved to the next radiator. For the far rooms with a huge drop, I opened the lockshield a touch instead of closing it. One lap around the house, then a second lap for tiny nudges.
Real numbers, because they help: lounge went from two turns open to three-quarters open and the drop moved from three to nine degrees. Hall from one and a half turns to half a turn, four to ten degrees. Box room from a quarter turn to a full turn open, sixteen down to eleven. I wrote the settings on masking tape next to each valve so Future Me doesn’t play this game from scratch.
Afterwards the house behaved. All rooms reached comfortable within about twelve to fourteen minutes of each other. No single radiator shouting. Boiler stayed at 50 °C without complaints. Return temps were sensible so it condensed more and cycled less. Bedrooms felt calmer instead of hot-then-cold swings.
Things I nearly messed up: spinning valves like a safecracker (quarter turns only), chasing matching numbers (you want consistent, not identical), and forgetting the TRVs (start with them open or you’ll “fix” the wrong thing).
Cost was nothing. Two cheap thermometers I already had, one screwdriver, about ninety minutes including a tea and moving the dog off warm pipes. Next grey afternoon I’ll try 45 °C flow and see if comfort holds. If it does, the bills drift down again. Small turns, small wins. That’s the whole point.
