After much help from these excellent forums I now know exactly what I want to have installed to replace my aging combi boiler.
I have decided to go with the Vaillant uniSTOR and ecoTEC plus system boiler, however, I've had a couple of Vaillant registered fitters around for quotes/advice and they have come up with a different combination of units:
The first fitter has suggested the following:
210 litre uniSTOR and ecoTEC 637
The second fitter has suggested something slightly different:
310 litre uniSTOR and ecoTEC 630
The recommendation of the second fitter has slightly confused me as I thought going for a larger cylinder would require a bigger system boiler, but in this case it appears not.
I was thinking about edging my bets and going for a 260 litre uniSTOR but I'm not sure which of the two boilers would be better. As one fitter said, "With the ecoTEC range you can always turn the output down, but if you under spec. the boiler you can't turn it up". This is true, but then why pay for a larger (potentially less efficient boiler) if a smaller one will do the job?
I may be splitting hairs here, but I would appreciate any advice.
The current boiler is a Saunier Duval 28E Thelia Twin. The house has 5 bedrooms, 2 bathrooms and an en-suite shower room. Both bathrooms have a bath and a shower. However, one of the bathrooms is in the (converted) loft and doesn't get used at all so can almost be ignored for the purpose of sizing the boiler. I have two teenage boys and a younger son, plus "the wife". As the teenage boys are now showering most days it is a constant fight for the shower every morning! Our current boiler can't cope with running two showers simultaneously. The worst case scenario for the new system is therefore to run 2 showers simultaneously for about 20-30 minutes in the morning. The baths are rarely used and so are not an issue.
I have decided to go with the Vaillant uniSTOR and ecoTEC plus system boiler, however, I've had a couple of Vaillant registered fitters around for quotes/advice and they have come up with a different combination of units:
The first fitter has suggested the following:
210 litre uniSTOR and ecoTEC 637
The second fitter has suggested something slightly different:
310 litre uniSTOR and ecoTEC 630
The recommendation of the second fitter has slightly confused me as I thought going for a larger cylinder would require a bigger system boiler, but in this case it appears not.
I was thinking about edging my bets and going for a 260 litre uniSTOR but I'm not sure which of the two boilers would be better. As one fitter said, "With the ecoTEC range you can always turn the output down, but if you under spec. the boiler you can't turn it up". This is true, but then why pay for a larger (potentially less efficient boiler) if a smaller one will do the job?
I may be splitting hairs here, but I would appreciate any advice.
The current boiler is a Saunier Duval 28E Thelia Twin. The house has 5 bedrooms, 2 bathrooms and an en-suite shower room. Both bathrooms have a bath and a shower. However, one of the bathrooms is in the (converted) loft and doesn't get used at all so can almost be ignored for the purpose of sizing the boiler. I have two teenage boys and a younger son, plus "the wife". As the teenage boys are now showering most days it is a constant fight for the shower every morning! Our current boiler can't cope with running two showers simultaneously. The worst case scenario for the new system is therefore to run 2 showers simultaneously for about 20-30 minutes in the morning. The baths are rarely used and so are not an issue.
