Solar Heating

steviebyrne

I'm sure this question has been asked already but I am wondering if anyone has recently installed solar heating in their home. Was it expensive over all? does it work? and has it been a cost saver on oil/gas?

RoundyMooney

I'll move this to the Renewable Energy room

muckety

We installed solar panels (3xpanels) a few years ago that we were told would run our underfloor heating for most of the year, with a gas boiler to back it up in the colder months. This has NOT been the case. We are refilling the gas tank every 6 weeks in winter (heating just less than 2500sq ft). In summer - from about next month on - it is reasonably effective but we reckon we will be a long time breaking even.

AckwelFoley

We installed solar panels (3xpanels) a few years ago that we were told would run our underfloor heating for most of the year

Im sorry to hear that..actually angry.. who ever sold them to you simply hadnt a clue of their job.

Depending on size of the house youd need more than double..closer to treble the amount of solar panels.. and with that still need back up.

Mothman

As per muckety's experience, I fail to see how solar panels can make a big impression on space heating. When it is most needest, the solar output is at its lowest.

What happens to all the excess in Summer and Autumn.

The only situation I can think of is if it were used in conjuction with a swmming pool. Size the system to give significant input in winter, the massive output in summer into swimming pool.

Ignoring solar panels, house design can make use of low winter sun with solar gain and yet exclude the high summer sun.

sydthebeat

following on from mucketys post and snypers response......

this is a typical comment people make when questioning the usage of renewables.
Salespersons will sell you the golden egg every time........
Its up to you the consumer to weigh up the pros and cons and make decisions based on all knowledge available.

3 sq m of solar panels probably would heat both space and water heating all year round in a passive certified house.... but the vast majority of houses built are not passive.

If you are going to base your space heating on solar collectors then forget about building a C or B rated house... even an A3 will be hard to heat.
The most important issues are the amount of passive solar gains (design) and the u value of construction elements (insulation).
After these you need to look at the control you have over the heating system to suit your needs.
You need to look at quality control of your build system (Thermal bridging, Airtightness... and, subsequently, ventilation).

when you have worked out what energy you need to heat the house, THEN and ONLY THEN, should you decide what heating source / fuel you require.

AckwelFoley

sydthebeat wrote: »

following on from mucketys post and snypers response......

this is a typical comment people make when questioning the usage of renewables.
Salespersons will sell you the golden egg every time........
Its up to you the consumer to weigh up the pros and cons and make decisions based on all knowledge available.

3 sq m of solar panels probably would heat both space and water heating all year round in a passive certified house.... but the vast majority of houses built are not passive.

If you are going to base your space heating on solar collectors then forget about building a C or B rated house... even an A3 will be hard to heat.
The most important issues are the amount of passive solar gains (design) and the u value of construction elements (insulation).
After these you need to look at the control you have over the heating system to suit your needs.
You need to look at quality control of your build system (Thermal bridging, Airtightness... and, subsequently, ventilation).

when you have worked out what energy you need to heat the house, THEN and ONLY THEN, should you decide what heating source / fuel you require.

You would need to get an energy assesment of your proposed plans in order to be able to make a decision, and this needs to be done by the professionals.

Reputable companies with qualified engineers will then be able to quantify the energy requirements. The method is relitavely simple calculations. If you feel the supplier is trying to sell you too much for what you need - then get the suppliers proposal;s checked independantly. However, the market is becomming more competative, a supplier is not going to try to over supply, because their quote will be higher than the competitors and if they under quantify.. it wuill be insufficent to heat the house and therefore responsible for altering it.

sydthebeat

snyper wrote: »

You would need to get an energy assesment of your proposed plans in order to be able to make a decision, and this needs to be done by the professionals.

Reputable companies with qualified engineers will then be able to quantify the energy requirements. The method is relitavely simple calculations. If you feel the supplier is trying to sell you too much for what you need - then get the suppliers proposal;s checked independantly. However, the market is becomming more competative, a supplier is not going to try to over supply, because their quote will be higher than the competitors and if they under quantify.. it wuill be insufficent to heat the house and therefore responsible for altering it.

I would go a step further and say that the energy requirement should be calculate at design stage, because design is one of tehmost important factors in energy requirements. Every Architectural firm should have an in house or dedicated energy auditor.

Mothman

While I agree with recent posts, there can be huge differences between families in their requirements. So a design for one family may not suffice another.

Does design have to encompass all possibilities?

sydthebeat

Mothman wrote: »

While I agree with recent posts, there can be huge differences between families in their requirements. So a design for one family may not suffice another.

Does design have to encompass all possibilities?

The 'design' i was referring to was a design to maximise the solar heating gains from the sun.
Whatever the requirements of the client as to accomodation within the building, the resultant concept should make maximum use of passive solar gains.
The design shouldnt encompass all 'possibilities', but all 'advantages'.

AckwelFoley

Mothman wrote: »

While I agree with recent posts, there can be huge differences between families in their requirements. So a design for one family may not suffice another.

Does design have to encompass all possibilities?

Well, ineffect, there are limited posibilities with a 3 bed house. Ie max amount of ppl.

Heat req is calculated upon cubic meter of the residential area. Current leg is @ 50kw/h per m i believe. BY 2009 10KW/H will need to be sourced from sustainsbles.

muckety

When our house was built, we looked for a design that would maximise passive solar gain, control (via zoning / thermostats) and quality of insulation etc. However, we are still putting 700 euro worth of gas in the tank every 6 weeks during the winter. This is due to having high ceilings and large rooms (which we knew were an extravagence but is working out much more costly to heat than we had originally thought).

Does anyone have advice on what we could do? We did install a wood burner in the largest room which is quite effective, but it doesn't feed the hot water tank (it was fitted retrospectively and it would have been expensive/messy to install a back boiler). I regret this now! We don't have a ventilation system that recycles the warm air - in fact, I believe our vents are part of the issue as they are very large and I can feel the cold air blowing into the house from them!

We have recently considered having an energy audit but have concerns about who to get to do this as it seems everyone is jumping on the bandwagon these days, so how to choose?

CJhaughey

muckety wrote: »

Does anyone have advice on what we could do? We don't have a ventilation system that recycles the warm air - in fact, I believe our vents are part of the issue as they are very large and I can feel the cold air blowing into the house from them!

I don't think that the high ceilings are a big problem, where the main problem lies is the fact that you don't have Heat recovery ventilation(HRV).
The old hole in the wall type ventilation is not the best for efficiency, Can you retrofit HRV?
That to me would be possibly the best way of reducing the heat loss, alternatively you could also reinsulate the N facing walls...

muckety

I googled HRV and it seems to be offered for New Builds or renovations - seems there is a lot of piping etc. which makes it difficult for retrofiting.

Are there any other suggestions? Can I get different vents that won't let in the cold air!??

AckwelFoley

muckety wrote: »

I googled HRV and it seems to be offered for New Builds or renovations - seems there is a lot of piping etc. which makes it difficult for retrofiting.

Are there any other suggestions? Can I get different vents that won't let in the cold air!??

Wht you need is a heat exchanger.

It basically transfers the heat from the exhaust air to the incomming air via a series of paper filters. The normal efficency of heat exchange is 75%...

It is possible to do a retro fit.. depending on the house involved. You can bocx off the rigid steel ducting too the outer wall of the house between the wall and the ceiling.. if you have attic space you can run it there.

One big advantage of these units is that they can give the house a fresh cycle of air every 2 hours, instead of every 48 hours without, and the filters can help ppl that suffer from air borne allergies.

muckety

Thanks! Any idea of the kind of company that installs this system? We don't have any attic space but there must be a workaround....