Gas vs.Oil AND how many Btu?

[peterd]

Thanks for the advice. After your comments, this is now the plan:

- 2 new high efficiency domestic combi boilers 120,000 btu odd each

- "insulate the hell out of the place" thanks for that - will star with draught proofing, then roof insulation 200mm then cavity in wall where there is a cavity, celotex wall lining inside where not, take u floorboards and insulate. See what I can do in terms of the garde listing for window improvements

- Use the 2 boilers separately, one for the main house, one for th holiday let

- build in the capacity for the boilers to work together if necessar or one in isolation in mild weather, after I've found out how t connect them to achieve this

- Keep the AGA ticking over on the oil at the lowest setting, It wil effectively just be used as cooker and heat for that room. Conversio to gas nice idea but bit too much hassle and less efficient than th new Combis.

- Go for large diameter pipework to all parts of the house

- multi zoning, with sub divided zones in bedrooms etc. Main zone fitted with Grundfoss Alpha auto variable pumps

- Seriously consider a thermal store Cheers, Pet

-- peterd

[Dave Liquorice]

Interesting idea, could do with something like that here. 38kW is rather to much during the summer. Not to mention the 12 gallons of water in the boiler alone...

It's only control system, PoP to do if you use a PLC to control the system rather than using conventional power switching in stats/valves and relays.

[Doctor Drivel]

Make that 400mm. The extra cost is negligible when installing and the gains greater. Look at Warmcell spray-in cellulose insulation. It makes a structure air tight too, so overall cheap when you consider the benefits.

then cavity in walls

It is not possible to have the flat as 100% self contained? It would be better this way.

Connect both "directly" to a thermal store. This solves any two boiler connection problems. Connecting two boilers directly to a red system can be complex and entails larger pipe headers

Best convert the Aga to gas and have also heating the thermals tore if need be. The Aga heating the store (slowly) will not be as efficient a state-of-the-art boilers.

Size the pieps properly.

Take the zones directly off the thermals store. The thermal store isolates the boiler from the heating system - a great advantage and simplifies matters.

Best say I will get one. For info on stores look at

Cheers,