MCS & heat pump heat loss calculations

[Nostrum]

Looking through the guidance notes it seems you now have to provide the customer with a room by room heat loss calculation as part of the survey pack.

How do the more experienced heat pump installers do this and how long does it take you?

I'm looking at using the CIBSE domestic heating design guide method, but can see this taking a long time , and then if the figures don't add up then i'm going to be wasting a lot of time in surveying. Do you lot charge for a heat pump survey, or take it on the chin?

The free calculators I have found either tend to go into so much detail my head starts to hurt, or they are more basic like Stelrad Stars with minimal options for U values etc. Do you know of any easy to use software packages, I saw a mention of Daikin but can't find it on the site?

Cheers in advance!

 

[SimonG]

How much detail are they after?, not down to r values in calculating u values?

 

[Nostrum]

Thats the thing, i'm not sure!

I'm thinking it could be more beneficial to make a fairly accurate calc on heat loss as most heating systems are oversized. You now have to supply the customer with a copy of the heat emitter guide which offers some advise on over sizing. Putting 2 and 2 together I came up with an assumption that if you can accurately prove that existing radiators are oversized then it will reduce the cost of install if you don't have to change the them and also provide a more realistic estimate of efficiency and running costs

I may of course be completely wrong but my head is spinning as I have had my head in the books all day!

 

[SimonG]

I like your assumption.

 

[Nostrum]

I've just realised MCS have released a heat loss calculator !!!

There is a saying that goes something like 'assumption is the mother of all F up's though' !

 

[eaton]

I use one supplied by my merchants for heat pumps, they use 2 manufacturers so have made a room by room calc inc floor, windows, walls etc it's very thorough, it then works out my heat loss at 50c flow and I input rads to suit each room, then it works out which unit and all the run costs etc. works very well and takes 20 mins tops

 

[eaton]

If changing rads I actually oversize the calc by another 10% for rads so I can drop flow temp to 45c for better run costs.

 

[Nostrum]

Where do you find the outputs for the older rad's that are no longer in production?

Is there any chance of a look at the calculator you use at all?

I'm currently jumping through hoops and writing down how I intend to hold quarterly meetings with myself to discuss things I have done myself and ways I can improve myself...

 

[eaton]

Rads are a generic calc, look at a lot of rads and they are very similar in output. Send me your email.

 

[mountainman]

Wouldn't the biggest problem be the age old one of not accurately knowing the U value of wall, ceiling and floor construction?

 

[eaton]

It gives loads of differant options on construction, most people have a good idea of what they have, if unsure I er on side of caution