Avoiding solar panels

Effects

I'm currently working out house design with an architect. He says as part of the DEAP calculation that we will need to have solar panels for water heating. Is there any way to avoid this? We are planning to have gas fired underfloor heating. As well as this we are putting in a stove with a back boiler. I've been told stoves don't go well with UFH so was thinking of having a small enough stove that will heat the open plan living space on the first floor, with the boiler heating a cylinder coil and two or three rads downstairs. I have access to a lot of firewood which is why I'm going with a stove.
I have two reasons for not wanting the solar panels. First is the expense and pay back period and the second is that we are building a house with a flat roof. I'd rather not the panels on a bracket adding to the overall height as we already have a neighbour planning to object to our build and I'd rather give them no reason to.
I haven't read too much into the DEAP calculation process as I just haven't had enough time to do so. Is it feasible to avoid solar panels if we can make energy savings elsewhere?

soundskin

I'd be more worried about the controls of your gas and UFH, you should be looking at very good weather compensating controls and a heating buffer. Avoid stats and actuators.
Stoves and UFH can work but it is a bit of work as your mixing open vented and sealed system.
True pay back on solar will be long period of time, agree with you there.

quentingargan

Effects wrote: »

I'm currently working out house design with an architect. He says as part of the DEAP calculation that we will need to have solar panels for water heating. Is there any way to avoid this? We are planning to have gas fired underfloor heating. As well as this we are putting in a stove with a back boiler. I've been told stoves don't go well with UFH so was thinking of having a small enough stove that will heat the open plan living space on the first floor, with the boiler heating a cylinder coil and two or three rads downstairs. I have access to a lot of firewood which is why I'm going with a stove.
I have two reasons for not wanting the solar panels. First is the expense and pay back period and the second is that we are building a house with a flat roof. I'd rather not the panels on a bracket adding to the overall height as we already have a neighbour planning to object to our build and I'd rather give them no reason to.
I haven't read too much into the DEAP calculation process as I just haven't had enough time to do so. Is it feasible to avoid solar panels if we can make energy savings elsewhere?

Your stoves will probably hammer your EPC and CPC in the DEAP software. Adding them to the mix may actually increase the amount of solar you have to fit. You could look at whether a heat pump would have enough renewable contribution to meet your needs.

Solar water heating would be complicated, but for electricity production you can mount PV panels on a fairly shallow slope - there are plastic mounting buckets for example that sit on the roof and have the panels at 15 to 25 degrees. I would be fairly optimistic that there will be a feed in tariff for electricity from PV in the next year or so, and that would make the payback feasible.

Have a close look at the exemptions allowed to planning for solar. The distance between the plane of a flat roof and the panel must not exceed 50cm - if your mounting system is less than 50cm high, you don't need to include the solar on the planning for less than 7 modules (12 sq m) of a PV array.

galwaytt

Well I've gas, UFH and solar and it (now) works well, so it's technically possible. I've a 1000L buffer tank, and the solar makes a substantial contribution.

I've seen a wood pellet install where I have gas - again with UFH and solar, and again it hasn't given any trouble either.

As for payback, well the way I look at it, every time the sun comes up, I have hot water. What's not to like about that ? (although I appreciate your planning issue).

Effects

Architect currently has raised roof light section where the panels are to go. Without panels the raised section can be lower and is below the eye line of the house planning to object.

Effects

quentingargan wrote: »

Your stoves will probably hammer your EPC and CPC in the DEAP software.

So even though I'm not using gas, as I'm using trees I've grown and felled myself, it counts as me using more energy? Think I need to have a proper read up on DEAP.

BryanF

Effects wrote: »

So even though I'm not using gas, as I'm using trees I've grown and felled myself, it counts as me using more energy? Think I need to have a proper read up on DEAP.

If your not using gas, why install it?

Effects

Plan would be to have gas for UFH and hot water, when it would be needed. I'd rather not have the stove as the only source of heat. If you have any thoughts I'd love to hear them.

ford2600

If you have so much wood, would a log gasification boiler work instead of gas?

Effects

Available space is an issue regards log gasification.

BryanF

Effects wrote: »

Available space is an issue regards log gasification.

How come?

quentingargan

Effects wrote: »

So even though I'm not using gas, as I'm using trees I've grown and felled myself, it counts as me using more energy? Think I need to have a proper read up on DEAP.

DEAP assumes that your stove will be used for 10% of your heating need. But typically your wood stove will be 70% efficient. Your gas would be in the region of 91% efficient. It is this loss in efficiency, plus the air tightness loss in having a flue pipe that does the damage in DEAP. I usually see a need for one or two more PV panels in houses that have a wood stove.

The stove must be certified as wood only. If it CAN burn turf, DEAP assumes that it will.

I've also seen PVs in the back garden. Unlike solar thermal, distance isn't a problem.

Effects

BryanF wrote: »

How come?

Building a relatively small mews house. No utility room and no out buildings/shed.

Effects

quentingargan wrote: »

plus the air tightness loss in having a flue pipe that does the damage in DEAP.

We were planning a sealed stove with an external air supply, does this make a difference?

galwaytt

Effects wrote: »

Building a relatively small mews house. No utility room and no out buildings/shed.

..that sounds urban, in which case I assume you have access to natural gas ?? If so, you'd be mad to not use it.

quentingargan

Effects wrote: »

We were planning a sealed stove with an external air supply, does this make a difference?

I'm not a registered BER assessor - Like many others it it feels like I did the training about a century ago. The manual is HERE. Page 17/18 covers flues. I couldn't see your type of stove ventilation mentioned, but you could consult your BER assessor about that.

Calahonda52

Effects wrote: »

We were planning a sealed stove with an external air supply, does this make a difference?

This won't pass muster as a sealed to room heating system as the door opens for stoking.
If the stack is less that 200mm then its a flue and not a chimney.

Get your man to "do the math" without the stove and to look at PV.

they come ballasted so are ideal for flat roofs, no fixings and if not visible I don't think planning will be an issue if you go over the limit, or you could do a section 5 maybe to see what they think if its not visible

freddyuk

Ballast "buckets" are pretty ugly affairs and may put people off PV just for aesthetics. I decent matrix system can be ballasted using flat concrete slabs which cannot be seen.

Effects

I would assume as a new build that we can have a bracket connected through the roof rather than ballasts.

MOTM

Effects wrote: »

We were planning a sealed stove with an external air supply, does this make a difference?

This isn't an open flue. It is considered a room sealed stove. Check with the helpdesk for the official answer that'll work at audit if in doubt.

quentingargan

Effects wrote: »

I would assume as a new build that we can have a bracket connected through the roof rather than ballasts.

Generally with any type of flat roof, you are better off not penetrating the roof, but using a ballasted system. For large systems there are nice ballast units, but you will only need 3 or 4 panels for a well built house, and if they are out of sight anyhow, the ballast bucket is a cheap and easy system. Might need a few extra rafters for the weight bearing, but that's easy enough in a new build.

sydthebeat

remember with a flat roof ballast box system, if and part of the system is over 500mm from the plane of the roof, it technically requires planning permission.