LPG combi boiler v unvented system

metalblue

Hi all,

I run on LPG and currently have an unvented pressurised system for hot water and CH..however I need to replace the boiler as it's broken down and I am really keen on lookin to go down the combi route as I can remove my pressurised hot water tank and put a shower in the space, however my plumber thinks I am a little mad. We don't really use the bath all that often and have a cold feed power shower and good water pressure. The price for doing the work between a combi or replacing like with like is about the same (combi about £300 cheaper). House has 17 rads / 1 bathroom / 1 shower room / 1 WC (which I plan on putting in a mixer shower if I get rid of the hot water tank). I do lose a lot of heat through the roof as there is not loft space so the CH needs to be on all day during the height of the winter.

Is a combi a good or bad idea? I am assuming it won't make any difference for the CH?

Thanks much

albyota

Welcome to the forum, it is completely your own decision, but I would tend to agree with your plumber, IMO combi boilers are OK in a flat or small house, low occupancy, if you have a flat roof I would consider having this redesigned to include insulation, if at all possible. cost?.... anyway I would stay with a ssystem boiler and unvented cylinder.

david29dpo

I to have this decision to make. I dont think you have to worry about the CH side of things, its the hot water rate. My main reason in having a combi is to free up space taken by the tanks. I have been looking at the Worcester range with the best hot water flow rate.

Canucklehead

metalblue wrote: »

Hi all,

I run on LPG and currently have an unvented pressurised system for hot water and CH..however I need to replace the boiler as it's broken down and I am really keen on lookin to go down the combi route as I can remove my pressurised hot water tank and put a shower in the space, however my plumber thinks I am a little mad. We don't really use the bath all that often and have a cold feed power shower and good water pressure. The price for doing the work between a combi or replacing like with like is about the same (combi about £300 cheaper). House has 17 rads / 1 bathroom / 1 shower room / 1 WC (which I plan on putting in a mixer shower if I get rid of the hot water tank). I do lose a lot of heat through the roof as there is not loft space so the CH needs to be on all day during the height of the winter.

Is a combi a good or bad idea? I am assuming it won't make any difference for the CH?

Thanks much

Good morning: keep the unvented cylinder as a combi (even a storage combi eg. Vaillant 937 or Worcester Bosch 440 CDI , both bulky items) would not provide the same volume of DHW to multiple drawoffs points as a competently sized and installed unvented cylinder

You should investigate insulation options to reduce heat loss first before you invest in a new CH system.

A combi boiler is not the panacea many believe them to be.;)

HTH

Canucklehead

PDM1

i agree, keep your existing style system, combis ok but you will at least have electricity to back up the hot water if boiler breaks down.

sometimes things are not worth sacrificing especially in the depths of winter!

you may not want to belive me but reply to me next March when winter is over