Plumbers & electricians in Snodland

The town sits on the west bank of the Medway between Rochester and Maidstone, with the North Downs rising behind it and the river forming the eastern edge of the parish. It grew on paper and on chalk. A mill was making paper here by about 1740, lime burning and then cement followed as Victorian London swallowed whatever the quarries could dig, and once the railway reached the town in 1856 the population trebled inside twenty years. Terraces went up along Birling Road and Holborough Road to house the men at the paper mill and the cement works, and plenty of those houses are still occupied.

Then Holborough shut. The cement works closed in 1984 and the quarry behind it lay idle for two decades, until Berkeley Homes began building on the floor of the workings in 2005.

What replaced it is Holborough Lakes, around twelve hundred homes raised in phases around flooded quarry ground, and it is a different species of building from anything else in ME6. Ham Hill trails south along Malling Road with its own older mixture. Paddlesworth Road climbs west out of the valley toward the chalk and the woods above it. Peters Bridge, opened in 2016 and the first new road bridge over the Medway since the motorway crossing at Borstal, links this bank to Wouldham and Burham opposite. The two ends of this parish share very little beyond a postcode, so a heating job here might be a solid walled terrace before lunch and a twenty year old house with cavity insulation and sealed units after it.

What a low flow temperature asks of the rest of a Snodland house

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Start with the number the whole argument turns on. A gas boiler in one of the Birling Road terraces is almost certainly pushing water out at somewhere near seventy degrees, and every radiator in that house was picked on the assumption that it always would. A heat pump has no appetite for that. Its efficiency drops the hotter it is asked to lift the water, so the sensible design figure is nearer forty, and lower again in a dwelling that holds onto its heat. The awkward part is that a radiator’s output is not a fixed quantity stamped on the back panel. It is a function of how much warmer the metal is than the air around it, and taking the flow from seventy down to forty roughly halves that gap. Output collapses with it, to somewhere between a third and a half of what the identical radiator delivered on the boiler. Nothing about the radiator itself has altered. The conditions it was chosen under have. That is precisely why swapping to a heat pump is a heating system job rather than an appliance change, and why the emitters in most properties have to get bigger, in awkward rooms to twice or three times the surface area they carry today.

So the honest opening move is a heat loss calculation, room by room, measured off the walls, windows and roof. Sizing a heat pump from the old boiler’s kilowatt rating proves nothing, since that boiler was very likely double what the house wanted.

Two further consequences arrive alongside. Pipe carries heat by moving water, and a heat pump shifts a great deal more of it than a boiler does, because the difference between flow and return is a handful of degrees instead of twenty. Eight and ten millimetre microbore, ordinary enough in anything replumbed during the seventies and eighties, can quietly become the ceiling on the entire system, and the index circuit may need opening up to twenty two. Stored hot water is the second consequence. A heat pump cannot fire on demand, so it warms a cylinder over a long slow reheat, and that cylinder wants a coil of far greater surface area than a boiler fed one, simply because there is so little temperature available to drive heat through it. Where all of this leaves any particular address genuinely depends on the address. Out on the Holborough Lakes streets, insulated and glazed to a modern standard from day one, the arithmetic frequently works. In a solid walled terrace under an uninsulated loft it may not, and telling somebody that before they spend money is part of the job.