Should I be paying for a Air source heat pump survey?

pharte

Hi all,

We are looking at having air source fitted to our home.

The company who came this weekend have said a survey is needed to calculate what we will need with basic drawings to make calculations.

The company have asked for a £200 fee to carry out the survey which will be taken off the total when we place the order.

Without knowing if it is either affordable on our budget or if the figure stack up for the system against the savings until we have a price we are reluctant to pay for the survey especially if we do not take their proposal.

The other consideration is we would look for 3 or more quotes from different suppliers before committing to anything, if all the companies want £200 each it will get ridiculous.

Any advice or previous dealings by forum members?

matelodave

I did it a different way. I drew up a plan of my bungalow with dimensions of the rooms, types of windows and sizes. Info on the the floor type, wall type, ceiling and roof together with info on insulation. and I specified what I wanted.

I also did a few sums of my own to check what I thought I needed in the way of heat and hot water to give me something to base my evaluation on - there are plenty of websites that have heat calculators which will help you do this.

I sent it out to six different companies for an estimate so I could compare costs and see what they were offering. Four actually replied and two wanted an up front payment.

I went and visted the two that replied and who didn't ask for an upfront payment at their premises (both about 20 miles away) to see what they'd got and to discuss my requirements.

Both had equipment set up and running so I could get an idea of what it all looked like. One sent and enginner round and the other was obviously a salesman and I chose the one who appeared to have most knowledge, both costs were about the same.

The one I chose sent me a proper quotation, detailing the kit they were supplying - this was seven years ago and I think the rules and specifications are a bit tighter now on what they've got to do so it's probably not unreasonable to charge for a fully spec'd quotation but most of them should be able to give you an estimate based on a reasonably detailed enquiry.

If you want to PM me, I've got some more info, but I wont be around until next week (after the bank holiday)

pharte

Great summary and advice.
As this is a property we've just bought and a heat pump is one of many jobs for consideration (including solar which won't give us a reasonable payback)
we have an oil fired boiler (no gas) a heat exchanger, swimming pool with warm air and dehumidifying, radiators through the house and hot water tanks.
it's bordering on commercial due to the size, we even have 3 phase electrics, two meters each running two tarriffs (economy seven and standard on each) even though there is nothing to use on economy seven.

so looking at all the possibilities and coming up with a best fit solution will be cruicial for us.

pharte

This is getting silly.

We've now had several visits from companies and had "estimates" for installation ranging from £30,000, £40,000 and even £140,000 (which was for ground source system)

It is apparent that the cost of the system is in line with the total RHI payment that will be paid back from the government over 7 years.
in effect, the "investment" of our own money is taken by these companies and paid back over 7 years in RHI payments.

My main concern is that the cost (in electricity) of running these units has not been quantified by the companies selling / installing until we managed to pin one down for a figure.

"working flat out a 16kw high temp ASHP will cost £320 per month to run 24/7"

Our demand will require two of these units

Our current combined electric and oil usage which covers all our heating and power needs (including heating a large swimming pool) is around half of this cost!!

So for the running cost per unit of £3840 (x2) total £7680 per year (not including the pool running cost)

Then add the cost of buying and installing the system and it gets ridiculous.

of course there is the RHI payment to offset the cost but after 7 years this ends.

Anyone have any differing opinions?

matelodave

For a start, they dont run flat out 24/7 (or they shouldn't if they are sized correctly and you've got decent insulation etc)

Ours is an 11kw system heating a 140sq.m 1986 detached bungalow with questionable cavity insulation, double glazed windows of 1999 vintage but decent loft insulation (400mm)

I reckon it uses around 2kwh a day to heat our water (but only to around 45 degrees) in the summer, probably more in the winter and up to 50kwh a day when it's really cold (-12 or so). The heating flow temperature is around 35 degrees when it's 10 degrees outside and 45 when it's zero or less.

Although the unit is set to heat the house 24/7 we have zone controls which set back the room temperatures when the rooms are not in use and increase it for when they are.

A heat pump has a very slow response so dont think of it operating like a conventional boiler - that will result in very high bills and very low satisfaction.

We've had ours for seven years, including seven winters, with some extremely cold periods and I'm very happy with our energy costs.

I'm guessing that heating a swimming pool is another problem and I'd guess that you wont get any RHI for that.

pharte

Got that Dave.

Can I question your costs to run your unit as we have been told that ours will need two x 48kw units to supply enough to heat our house at 1,000 square meters.

If the cost of using a kwh in electric (to run the heat pump) is 17p we calculate our cost to produce the equivalent kwh in oil at 4.3p (based on our current oil price per litre)

Your usage of 2kwh per day for the summer 6 months and 50 kwh per day for 6 months in winter will give an approx demand of 9490 kwh per year.

At 17p cost to produce a kwh this will give a running total of £1,614 per year for heat and water.

Our current calculation for our house at approx 1,000 sq mt using oil boiler running at 87% efficiency @ 36.61 p per litre giving 9.33 kwh per litre which gives a kwh unit price of 3.9p

so...... 3.9p per kwh using oil
5p per kwh using heat pumps (based on an average COP of 3.7)

Many hours spent doing calculations which we are sure are correct and will make sense.

Basically at the current oil price / electricity price we are no better off installing heat pumps.

matelodave

We dont use 50kw a day all the time in the winter. My total energy consumption for last year - heating, hot water cooking, washing, cleaning etc was 7000kwh.

We only generate heat when it's required and the requiremnt is in proportion to the outside temperature and the inside temperature required. It also graphed the energy consumption on a monthly basis.

We presently pay 11.3p/kwh which at an approx COP of 3 = around 3.7p/kwh.

It took me some time to optimise our unit but I tried to understand my heating requirements. My unit is a Daikin and they had a simulator which allowed me to enter my heating requirement and it calculated the size of unit required based on my needs and the local temperatures.

IMO if you've already got oil then stay with it as the difference in cost probably isn't worth changing - your radiators and stuff wont be suitable, so the cost to change would be quite high.

We were starting from scratch - refurbing our bungalow and getting rid of rusty manky old storage heaters so we had a different requiremet to you. We also installed underfloor heating.

as I said I've got some info on what we did which you are welcome to see - just PM with your e-mail address and I'll send you a copy. It's also got graphs of my monthly energy consumption for about six years

silverwhistle

pharte wrote: »

As this is a property we've just bought and a heat pump is one of many jobs for consideration (including solar which won't give us a reasonable payback)

Have a mooch over to the green solar forum (I forget the correct title) and ask a few questions. You may have already done a pretty thorough analysis, but there might be a few helpful thoughts. They'll certainly put you right if you get quoted silly prices as per your ASHP quotes! I certainly think you're on the margins of a decent payback period, but perhaps not as bad as you think. Panel (and inverter) efficiencies have certainly gone up in the four years since i bought my system.

I've had solar a few years so obviously benefit from far better FIT rates, but you would benefit from far greater own usage. I have a diverter to put spare energy to my hot water tank but still export rather a lot (still get the FIT of course). As I also only have a small 3 bed house and a wood burner I only import <1800 wh a year (gas and electric) so our circumstances are a bit different!

lovesgshp

Are you going to be heating the whole property all the time, as otherwise you could reduce the heating need to certain rooms by zoning them.
The pool heating is normally in many situations just for the off peak months of the summer and would alternate between house and pool depending on the programming of the unit. Alternatively you could just install a pool heating ASHP that would work on its own and probably be much cheaper.
140K seems very expensive for a GSHP.
Confused a little, as you say in one post you need 2x48kw units "(Can I question your costs to run your unit as we have been told that ours will need two x 48kw units to supply enough to heat our house at 1,000 square meters.)"
and in a earlier post 2x16kw, ( "working flat out a 16kw high temp ASHP will cost £320 per month to run 24/7")
.Our demand will require two of these units"

ASHP will cost more to run, but you would have to balance the calculations against a GSHP which is more efficient to lower temperatures and which I think the RHI is better for people in the UK.