16 radiatrors advice required

[walter baggie]

after extending the house i now have 16 rads to run aswell as 3 thermostatic showers(en suites) is it a good idea to run two combis or is there an alternatve way ,i was planning to have a combi for upstairs and one for downstairs,currently i have a glowworm 100 e which has ran 9 rads and 1 thermostatic shower which has been excellent ,please advice

 

[chrishutt]

The number of rads doesn't mean an awful lot. What you need to do is total the heat outputs. The Glowworm 100e would have an output of 28 kW, which is almost certainly more than enough for your rads, but not adequate for your potential max. hot water demand.

If being able to run all your showers and other outlets simultaneously is important to you, you should consider an unvented cylinder (subject to having sufficient mains water flow - but that applies in any event). Such a cylinder could be heated indirectly by the boiler, which could also continue to provide some outlets as a combi. This way you wouldn't need any new combis.

 

[Bahco]

The pros will probably steer you into an unvented system. Two combis will cost an arm and a leg to run and maintain though

 

[ChrisR]

Run 2 showers off one combi - you'll soon learn not to try to use both at once, and put an electric in the 3rd. Then you'll have HW when your combi decides it needs a rest.