Central Heating Installation in Milton Keynes

Everything follows from this and it is the step most often skipped. A room-by-room heat loss calculation works out how much heat each space actually needs, based on its dimensions, its external walls, its glazing and its insulation.

From that you get radiator sizes, and from the total you get the boiler output. Doing it the other way round, picking a boiler and then fitting whatever radiators fit the wall, is how you end up with a system that is oversized in some rooms and undersized in others.

Covered in more depth on our boiler installation page, but the short version is that mains flow rate and simultaneous bathroom use decide it. A combi for most one and two bathroom properties with a decent main. A system boiler and unvented cylinder where more than one bathroom is in use at once, or where the mains cannot support a combi.

This is the part that has changed and that most people have not caught up with.

Part L of the Building Regulations now requires new and fully replaced wet heating systems to be designed for a maximum flow temperature of 55°C, rather than the 75 to 80°C older systems ran at. The reason is efficiency: a condensing boiler only condenses, and only reaches its rated efficiency, when the return temperature is low enough.

The consequence is that radiators need to be larger to deliver the same heat at a lower temperature. A radiator sized for 75°C flow will underperform at 55°C. This is precisely why a boiler swap onto original radiators often fails to deliver the bill reduction people expect. The boiler is capable of running efficiently. The system will not let it.

Designing the whole system at once is how you actually get the efficiency you paid for.

A full installation is the moment to deal with pipework that is not fit for purpose, particularly microbore that has silted up, or runs that were extended for an extension without the capacity being reconsidered. Doing it later means lifting the same floors twice.

At minimum, a programmer, a room thermostat with boiler interlock, and thermostatic valves on radiators other than the one in the room with the thermostat.

Beyond that, zoning is worth considering in larger properties: separate circuits for upstairs and downstairs, or for a converted loft or extension that is used differently from the rest of the house. Weather compensation, which adjusts flow temperature to outside conditions, is the strongest performer for efficiency. Smart controls are more flexible and easier to live with. Both satisfy Boiler Plus requirements on a combi installation.

A large share of the 1970s and 1980s Milton Keynes housing was plumbed in microbore, typically 8mm or 10mm copper running from a manifold to each radiator. It installs quickly and it works, but the small diameter silts up with magnetite far more readily than 15mm pipe.

On a full system installation, microbore forces a decision. You can flush it and keep it, which is reasonable if it is in good condition. You can replace it, which is more disruptive and more expensive but removes the problem permanently. What you should not do is fit a new boiler and larger radiators onto silted microbore and expect the system to perform.

Beanhill, Coffee Hall, Netherfield, Fishermead, Conniburrow and Bradville are where this comes up most.

1980s and 1990s estates, Furzton, Emerson Valley, Shenley Brook End and Loughton. Many still on a system boiler and vented cylinder from the late 1990s, with radiators of the same vintage. These are the properties where a full system replacement makes the most difference, because everything is at end of life simultaneously.

Newer estates, Brooklands, Whitehouse, Fairfields, Oakgrove, Tattenhoe Park and Glebe Farm. Underfloor heating on the ground floor with radiators above. Underfloor runs naturally at low flow temperatures, so these properties are already part-way to what Part L now asks for, and the upstairs circuit is where the design attention goes.

Older property in Stony Stratford, Newport Pagnell, Olney and Wolverton. Solid walls mean higher heat loss and therefore larger radiators, which is a real constraint in rooms with limited wall space. Worth resolving at design stage rather than discovering on fitting day.

Milton Keynes averages around 300 mg/l of calcium carbonate through Anglian Water, MK8 measures roughly 317, and the UK average is 207. On a sealed heating system the water is not replaced, so the heating circuit itself is largely protected. The exposure is on the domestic hot water side and on any system that gets topped up regularly. We fit a scale reducer on the cold mains feed as standard.