Solar Panels/Tubes

sasol

Hi,
I have just started a new build - 2,600 sq ft story and a half, south facing.

I have been talking to a plumber about heating the house and domestic water and he recommended Solar Tubes (Thermomax). Just wondering if anyone has experience of using these as opposed to the ordinary solar plates ??

Would they recommend them ? Do they actually heat the water sufficiently on cold/hazy/dull days ?

I'd also been interested in hearing peoples opinions of solar panels and/or heating in general as I have been in two minds whether or not to install solar.

Some people I have been talking to swear by it but others they the investment does not equal the benefit to get got.

Any help/opinions would be greatly appreciated.

Technophobe

Hi,

I am in the same boat as you..started new build and looking at these options...all I know is that any plumbers I have spoken to so far has said Tubes are better than panels for obtaining some heat/water on dull days....!!

GoneShootin

Someone mentioned to me in passing that the tubes in need to be replaced every 10 years - is that true? I'm starting a build myself soon

Borzoi

GoneShootin wrote: »

Someone mentioned to me in passing that the tubes in need to be replaced every 10 years - is that true? I'm starting a build myself soon

Far from it, I think Thermomax give a long warranty, though probably not ten years. From speaking to them, they estimate the lifetime of the tubes to be 20 years plus

gears

From what I know of the Thermomax tube they are not a true vacuum tube panel as they have a flat plate attached to their evacuated tube and so behave more like a flat panel.
I'm sure some on else may have a different opinion on this but if you want the advantages of a vacuum tube I would go for a different model and there are many out there.

MickLimk

First up, I am biased in favour of the technology as I'm a solar installer but have no affiliation with any particular brand or product.

sasol wrote: »

Hi,
I have just started a new build - 2,600 sq ft story and a half, south facing.

I have been talking to a plumber about heating the house and domestic water and he recommended Solar Tubes (Thermomax). Just wondering if anyone has experience of using these as opposed to the ordinary solar plates ??

Would they recommend them ? Do they actually heat the water sufficiently on cold/hazy/dull days ?

I'd also been interested in hearing peoples opinions of solar panels and/or heating in general as I have been in two minds whether or not to install solar.

Some people I have been talking to swear by it but others they the investment does not equal the benefit to get got.

Any help/opinions would be greatly appreciated.

Thermomax have a reputation as being one of the best performing evacuated tube solar systems on the market. The figures from their EN cert bear this out but the cost of Thermomax systems has generally more than reflected this slight performance advantage. I tried figuring it out once and reckon that it's about a 4-5% performance advantage over other commonly installed brands but a lot more expensive than 4-5%. You can get better price/performance ratio products out there so by installing a couple of extra tubes for lower cost, you could have a better performing system...

A lot of the performance differences of a system are down to how it's sized, controlled and installed. A poorly sized system will not perform so tailoring a system around the hot water patterns of the customer is the best way. Often, oversizing the system can add a small amount to the initial cost but will provide hot water for a longer period of the year. In this case, it is essential to fit a heat dump mechanism (perhaps a towel radiator or two) to prevent repeated stagnation of the system during the peak summer months.

Technophobe wrote: »

Hi,

I am in the same boat as you..started new build and looking at these options...all I know is that any plumbers I have spoken to so far has said Tubes are better than panels for obtaining some heat/water on dull days....!!

Yep, agree that for typical overcast Irish weather, tubes are generally better.

GoneShootin wrote: »

Someone mentioned to me in passing that the tubes in need to be replaced every 10 years - is that true? I'm starting a build myself soon

The vacuum in the evacuated tube should last about 20 years or so. A supplier on here has quoted approx €5 (I think!) to replace the glass part of a tube as the heat pipe inside can simply be transplanted to the new tube. It's more likely to cost about twice that from prices I've seen but each one should last 20 years anyway...

gears wrote: »

From what I know of the Thermomax tube they are not a true vacuum tube panel as they have a flat plate attached to their evacuated tube and so behave more like a flat panel.
I'm sure some on else may have a different opinion on this but if you want the advantages of a vacuum tube I would go for a different model and there are many out there.

Thermomax have a slightly different design alright as they have bonded an absorber onto each heat pipe. In the case of these, the entire evacuated tube is sealed and cannot be replaced as outlined above making it a lot more expensive to replace if broken by a sliotar/football/large rock...

muffler

Moved to the RE forum

Evergreen

If your orientation is between SSE and SSW with an inclination of 30° to 55° then spending money on evacuated tubes is not worth the extra investment.

In terms of warranty, if you are not getting 10 years on either flat plate or tubes then keep away from them.

Evacuated tubes can last up to 30 years if they are built correctly, always look for stainless steel U-Tubes, as opposed to copper ones. With the high temperatures reached in tube collectors the constant steaming and condensing in the tube will cause copper pipes to oxidise internally. As a result companies that manufacture both stainless and copper piped tubes will always offer 10 years warranty on the stainless and only 5 years on copper piped systems.