[Nick Benny]

Looking for some knowledge/experience of the renewable technology world!

We have a small 19th century solid walled stone farmhouse on the edge of Dartmoor, we are insulated and double glazed, we have only been here since last November and are currently planning a modern construction extension to give us 4 bedrooms, about 15 rooms in total.  We also have a barn with a south facing roof about 12m long by 3m sloping height.  We also have an unheated 10m swimming pool with a reasonable pump and filtration system.

Our water heating and central heating is provided by oil via a Rayburn in the current kitchen.

As part of our extension I have been looking into renewable technologies and have had a couple of 'experts' looking into our requirements, both have said a heat pump, solar thermal and solar PV combination is the way to go.

One of them has suggested using the large barn roof for Solar Thermal to heat the pool via a heat exchanger and also provide some of the domestic hot water and heating requirement and topping up via the heat pump, combined with a smaller Solar PV installation on the house roof to provide us with some of the power to run the heat pump (during the day) and get something from the feed in tariff.

The second has recommended almost the opposite, install a massive quantity of solar PV on the barn circa, 46 Panels! 16kW, and using this to do an immersion for the pool and another for the domestic water and heating, again via the heat pump.

What I am looking for is whether anyone else out there has been through a similar exercise and could give us the benefit of their experiences?

If the figures are correct the first option will give pay back in a little under 10 years when you take into account the Renewable Heat Incentive for the Solar Thermal and the FIT for the Solar PV.

I am still waiting for the second option figures.

Also are there any companies you would recommend (or not) in the Devon/Cornwall South West area.

Nick

[Dreich Pete]

I can't offer any solid advice for you, I'm afraid, but as somebody who has been mulling over his own options for a couple of months I have picked up a couple of bits of info and a couple of little concerns.

I read something the other day that stated that the government has rejected requapests to reverse it's position on solar heating AND solar pv installations being eligible for grants and FIT support. Apparently they are refusing to accept that the two things used together are more effective and more in line with the spirit of current policy philosophy. There is a relatively new technology that combines these but is specifically excluded from the deals available. A bit short sighted, but what would we expect from a government who's Energy minister doesn't believe in climate change?

The FITs are about to change again, and a further reduction is on the cards (although not such a big cut as last time (when they managed to devastate the renewables industry in the UK). This does raise a concern in my mind that not only is your FIT contract between you and the government, not the energy company, and therefore very susceptible to them breaking the contract or changing the terms whenever the political winds blows a different direction, but the payments are only index linked to inflation, not the price the surplus electricity is sold on for by the energy company. In effect, the higher they raise their prices the more profit they make from our surplus energy fed into the system. Nice deal for them, eh?

I've yet to see a justifiable set of figures to show that you would be in "profit" after only 10 years once you have factored in the potential for repairs, replacement of the inverter (expected to last no more than 10 years and costing upwards of £600 for the unit alone), and the relative falling behind of revenue versus costs.

My starting point is to be off-grid and self-sufficient, and anything else would be a bonus.

[mab]

I would be wary of anyone suggesting a heat pump for an old solid stone walled house unless the house has had substantial insulation added to the walls (either as internal or external cladding) as heat pumps only work well with very well insulated and draught-proofed houses.,

Having said that, a heat pump should work well for the swimming pool as it can use low temp heat; so maybe that is what they were thinking.

I don't know about FIT's and RHI's though so I probably can't be much help.

[Dan]

We have a late 19th century stone-built farmhouse which we renovated in 2010. It's only 3 bedroom though, so a lot smaller than your's!

After consultation with the Energy Saving Trust - well worth approaching if you want an independent opinion - we went with a ground source heat pump coupled with a 4kW PV array. They came out and did a survey and sent a comprehensive report of options.

It has worked out very well for us. The heat pump is working efiiciently, and with the benefit of the FIT we're almost cost-neutral for energy (our only energy source is electricity).

As mab says the heat pump is only viable if you have very good insulation. We stripped our house back to bare walls and installed new windows throughout as part of our renovations.

You say your place is insulated and double glazed, what you really need is to establish the U-value of the building - http://www.architecture.com/SustainabilityHub/Designstrategies/Earth/1-1-1-10-Uvalues%28INCOMPLETE%29.aspx

That will let you make an informed decision about heating capacity, and therefore the system installation options. If none of your 'experts' have calculated a U-value they can only be guesstimating your requirements.

HTH, if nothing else I'd highly recommend the EST as a first port of call.

[regen]

How much insulation and where? What is the uvalue? Without very good insulation you will never get the best and hence a payback from renewable. What is the floor area - you say small but 15 rooms aint small! How important is heating the swimming pool?
As far as PV vs Solar thermal, PV wins every time but it depends how much your DNO will let you connect without additional cost.

However without the basic facts detailing actual current energy usage,square footage and insulation details its a waste of time speculating.

Regen