I would appreciate some advice regarding my thinking-out-loud assessment of our heating system, and the best way to improve it somewhat if at all possible.
I've recently bought a relatively new (2007) 3-bed 2.5 storey semi which is obviously very well insulated and given the variety of sizes of radiator appears to have had the heating system designed through calculation, even if just following rules of thumb. The radiators, with output figures obtained from similar-looking Flomasta spec sheets, are:
(Room HxW Type Output) Kitchen 500x700 Double 1048W Hall 500x600 Double 898W Downstairs Loo 300x400 Single ~250W? (a real tiny one - I think it looks great!) Lounge 600x1000 Single 948W Conservatory 600x600 Double 1041W Front Bedroom 500x1000 Single 812W Rear Bedroom 500x1000 Single 812W Guest Bathroom 600x500 Double 868W Top Bedroom 400x700 Double ~1000W? En Suite 600x500 Single 488W Dressing Room 600x600 Single 570W
Total: 8735W
The boiler is a condensing Ideal Icos HE15 (I know - it's probably not the best place to start but it's what we've inherited and it seems to work well enough so I'm not looking to replace it just yet) which can modulate between 8.8kW and 14.6kW. It's an S-plan layout run in 10mm (the branches at least - I note the presence of 22mm at the boiler end and within the airing cupboard), with a digital CH stat in the lounge and a sealed indirect cylinder for the HW. The neighbours are only present at the weekend so for all intents and purposes I think their house is unheated most of the time.
I have a few issues that I'd like to address:
- Whilst I have yet to perform a full and proper observation the boiler appears to cycle a fair bit even before the house is up to temperature. I am wondering if this is because the total radiator output (even before any necessary derating) is at/below that which the boiler can modulate down to? That is, the system cannot get rid of the heat quick enough so the boiler has no option but to cut out? As described below I am planning on increasing the size of some of the radiators - would this help?
- The full-width conservatory was built after the house, and I am pretty sure that the 600x600 Double 1041W radiator in there was originally in the lounge under the window of the then outside wall i.e. they simply moved it from the inside to the 'outside'. It appears that this radiator is inadequate for heating the conservatory in colder weathers and whilst it has not been too much of a problem yet I think it may well be in the winter. For better or for worse we want to use the conservatory all year round so should I replace this radiator with something bigger? Or should I just supplement it with electric heating, perhaps a portable convector heater, as required? The latter might be beneficial for those times when we need a little heating in there when the CH is off (e.g. cooler summer nights).
- Given the suspected re-siting of one of the lounge radiators into the conservatory this has left just the 600x1000 Single 948W in the lounge and it seems to struggle by itself to bring the temperature up in any reasonable time i.e. the rest of the house seems to reach target temperature (as set by their TRVs) well before the lounge yet I can confirm the lounge radiator is very hot to the touch so it does seems to be trying. I was thinking of replacing it with a 600x1400 Double 2428W (maybe bigger?) thus bringing the heat output in there back up to 2kW+ as originally designed. Does this sound sensible? Would it help with the cycling? The stat is in the lounge hence no TRV. The lounge opens into the conservatory, and for various reasons we may well want to keep the doors to it continuously open (or at least partly), and so it is obvious it will also be partially attempting to heat the conservatory too. I could add an additional radiator back in there (perhaps where the original second one was) but that'd be a bit more work - replacing the single radiator would be much easier.
Any thoughts? Sorry for the waffle, but hopefully it describes the situation for you to be able offer some advice.
Mathew