Combi vs tank - which should I go for?

[ShaunCorbs]

Unvented or stick an electric shower in the new e suit and combi then

 

[EvilDrPorkChop]

To be fair, at the quoting stage I wouldn't be measuring rooms and calculating room sizes for heat outputs. From experience you generally have a rough idea of what will be needed etc. If I spent every time calculating figures for each job I priced, then i'd not have any time to do any actual work, and I bet half the time i'd be wasting my time and doing the work for the plumber they actually go with cause no doubt someone will be cheaper.

Whilst I wouldn't expect it at quoting, I would like to think once someone has got the job that all the necessary calculations would be done as @SJB060685 says as I usually do. 9/10 i'm usually right with my original guesstimate.

 

[ShaunCorbs]

Sys / heat only I work the room sizes out or worst case I work out the existing rads

Combi cold water flow rate

 

[b21playa]

Our existing rads are rubbish, I’ve been trying to replace them along with upgrading pipework to accommodate. I get whole house (20ish rads over 3 floors) at around 120,000 btu based on online calculators and know very little insulation and solid brick walls.

 

[SJB060685]

If a thorough calculation is completed you will arrive at the most accurate result. Having said that there are often cases where the homeowner just doesn’t know what, if any insulation is present. Times like that you would use quick reference guides but as I said above these can be way off at times. Once you have an idea of your loads then you can start designing the system. Is the customer happy with a high temperature system? Or do they want to maximise efficiency as much as possible and have a low temperature system installed and so on and so on. Before any of this can be decided and priced up and quoted for you need those initial heat loss figures.

 

[b21playa]

If a thorough calculation is completed you will arrive at the most accurate result. Having said that there are often cases where the homeowner just doesn’t know what, if any insulation is present. Times like that you would use quick reference guides but as I said above these can be way off at times. Once you have an idea of your loads then you can start designing the system. Is the customer happy with a high temperature system? Or do they want to maximise efficiency as much as possible and have a low temperature system installed and so on and so on. Before any of this can be decided and priced up and quoted for you need those initial heat loss figures.

Hi

This is my own house, looking for get heat into it. It takes hours for it to heat up, our previous house was never like this.

 

[SJB060685]

Yes I know mate. My questions were generic ones not specifically asking you . Excuse my ignorance but didn’t you create a post the other day about pipe sizes feeding radiators?

 

[b21playa]

Yes I know mate. My questions were generic ones not specifically asking you . Excuse my ignorance but didn’t you create a post the other day about pipe sizes feeding radiators?

Yes I did pal. I’m trying to plan everything and changing radiators while I’m sorting a few rooms out downstairs. The boiler/tank will be changed before kitchen is completed as it’s currently in a cupboard in there. Hot water flow is not good and I’d like to remove tanks in the loft

 

[SJB060685]

Yes I remember that post and that your current system is a shambles. To be honest from what I remember of the other post is if any of those that have used your existing system as a reference to supply you with a quote so far then forget them. You need a good installer/firm who are going to do everything required and thoroughly.

 

[b21playa]

Yes I remember that post and that your current system is a shambles. To be honest from what I remember of the other post is if any of those that have used your existing system as a reference to supply you with a quote so far then forget them. You need a good installer/firm who are going to do everything required and thoroughly.

All figures are based off calculate I’ve used. You’re right the existing system is no good so I’ve disregarded everything in it, everything needs renewing, apart from pump and zone valves which are 3yrs old