nedseg
Well-Known Member
Simple question, eh? None of this solar stuff (esp hot water) is simple, and I inherited kind of a botched system.
Short answer: Not currently - DHW only. I had the solar radiant heating sub-system disconnected.
Long answer:
The solar system was designed and plumbed (2003-4? by previous owner) to feed infloor radiant (finned copper) as well as DHW, but even with 4 - 4x8 panels it never generated high enough temps for that (pipes barely got warm on the sunniest winter day), and probably also sucked heat from the DHW loop (also older controller).
So I had the infloor radiant circuit removed from the solar system and installed a Triangle Tube uber-efficient boiler for the radiant loop - expensive, but paid for itself in less than 4 years (back up heat was electric baseboard!)
Last year I replaced the 4 failing 20+ yr old water panels with 2 new ones (20yr warranty), and new controller, and am now getting 130+ deg in the 50 gal DHW pre-heat tank on any sunny day, year round, or something like 80% of my hot water usage.
But now I have a monster 100gal clay lined radiant pre-heat storage tank just sitting there, plumbed but not in use, and too heavy to remove and not worth anything b/c of that.
Interestingly, after years of searching for a good knowlegeable solar/heating guy, I finally found a commercial HVAC company who has guys who really know their shit (apparently solar HW is dead for residential, but is still in demand for commercial installs).
They inspected the TT boiler and said it was still in perfect condition after > 6yrs use, should easily expect another 15-20 yrs life out of it, and that it was sufficiently oversized (as intended) to also handle DHW (plus another zone, if I wanted!, in fact it needs 'more load' than I currenlty have to run at top efficiency!)
(2000sq ft house, 200ft in-floor copper, 110,000(?) BTU boiler, Wisconsin winters.)
He advised that when I'm ready to take the next step (when the 'base' electric HW heater fails) and add a DHW 'indirect' loop to the boiler, I should consider re-connecting the radiant storage tank as kind of a 'storage capacitor', mostly b/c it would be cheap to do ...but did NOT discuss whether than should be connected to the solar system (probably not, as the solar HW as is just covers my daily needs, and I'm still kind of 'tree limited' in solar output).
All of this was on top of the $30k (!) the last owner apparently put into rebuilding the original 90s vintage system that had 8 storage tanks which rusted out and filled the small boiler room with rusty water, meaning the entire equipment room had to be gutted and rebuilt from the studs out!
So far I've probably invested around $15k for a 'modern' solar DHW and gas boiler refit (oh, and the house was all electric, so I had to bring a gas line in too!), and am thinking another $5k to add indirect HW to the boiler (but could easily get by with another much cheaper electric one), and hoping I can qualify for a modest solar PV system for under $5k. (These are all for commerical quality '20yr warranted life' systems, not cheap mnrds crud.)
My goal is to get my utility bills down to <= $50/mo ), and add solar PV as a hedge against nat. gas price increases (as well as electric), but from here on out the payback times will be much longer.
THe math for total utility bills looks like: Before upgrades: ~$4k/yr. Current: $1500/yr. Goal: $600/yr (or less).
The 'pro' HVAC guy said that it's now actually cheaper (if you have a good solar PV site!) to use solar PV for (electric!) hotwater than hot water panels (!), but that (for now), gas boilers are THE most efficient/cheapest way to do both, but leaves you vulnerable to possible future gas price hikes.
So, pretty much like the guy said in the (referenced earlier) video/presentation, the bottom line is kind of 'meh' on solar of either variety, other than as a hedge bet, or a costly investment to get to low bills later on.
BUT, my goal is minimal bills in retirement, esp as I 'age out', and Best Comfort Possible: the TT boiler gives me really warm floors upstairs and ceilings below, which for me is a true LUXURY, and The Best Heat Ever (and no damned set-back or fancy smart Tstats either!)
If I were starting from scratch today, I'd go with a super high efficiency gas boiler for DHW and heat, plus PV for electricity.
Short answer: Not currently - DHW only. I had the solar radiant heating sub-system disconnected.
Long answer:
The solar system was designed and plumbed (2003-4? by previous owner) to feed infloor radiant (finned copper) as well as DHW, but even with 4 - 4x8 panels it never generated high enough temps for that (pipes barely got warm on the sunniest winter day), and probably also sucked heat from the DHW loop (also older controller).
So I had the infloor radiant circuit removed from the solar system and installed a Triangle Tube uber-efficient boiler for the radiant loop - expensive, but paid for itself in less than 4 years (back up heat was electric baseboard!)
Last year I replaced the 4 failing 20+ yr old water panels with 2 new ones (20yr warranty), and new controller, and am now getting 130+ deg in the 50 gal DHW pre-heat tank on any sunny day, year round, or something like 80% of my hot water usage.
But now I have a monster 100gal clay lined radiant pre-heat storage tank just sitting there, plumbed but not in use, and too heavy to remove and not worth anything b/c of that.
Interestingly, after years of searching for a good knowlegeable solar/heating guy, I finally found a commercial HVAC company who has guys who really know their shit (apparently solar HW is dead for residential, but is still in demand for commercial installs).
They inspected the TT boiler and said it was still in perfect condition after > 6yrs use, should easily expect another 15-20 yrs life out of it, and that it was sufficiently oversized (as intended) to also handle DHW (plus another zone, if I wanted!, in fact it needs 'more load' than I currenlty have to run at top efficiency!)
(2000sq ft house, 200ft in-floor copper, 110,000(?) BTU boiler, Wisconsin winters.)
He advised that when I'm ready to take the next step (when the 'base' electric HW heater fails) and add a DHW 'indirect' loop to the boiler, I should consider re-connecting the radiant storage tank as kind of a 'storage capacitor', mostly b/c it would be cheap to do ...but did NOT discuss whether than should be connected to the solar system (probably not, as the solar HW as is just covers my daily needs, and I'm still kind of 'tree limited' in solar output).
All of this was on top of the $30k (!) the last owner apparently put into rebuilding the original 90s vintage system that had 8 storage tanks which rusted out and filled the small boiler room with rusty water, meaning the entire equipment room had to be gutted and rebuilt from the studs out!
So far I've probably invested around $15k for a 'modern' solar DHW and gas boiler refit (oh, and the house was all electric, so I had to bring a gas line in too!), and am thinking another $5k to add indirect HW to the boiler (but could easily get by with another much cheaper electric one), and hoping I can qualify for a modest solar PV system for under $5k. (These are all for commerical quality '20yr warranted life' systems, not cheap mnrds crud.)
My goal is to get my utility bills down to <= $50/mo ), and add solar PV as a hedge against nat. gas price increases (as well as electric), but from here on out the payback times will be much longer.
THe math for total utility bills looks like: Before upgrades: ~$4k/yr. Current: $1500/yr. Goal: $600/yr (or less).
The 'pro' HVAC guy said that it's now actually cheaper (if you have a good solar PV site!) to use solar PV for (electric!) hotwater than hot water panels (!), but that (for now), gas boilers are THE most efficient/cheapest way to do both, but leaves you vulnerable to possible future gas price hikes.
So, pretty much like the guy said in the (referenced earlier) video/presentation, the bottom line is kind of 'meh' on solar of either variety, other than as a hedge bet, or a costly investment to get to low bills later on.
BUT, my goal is minimal bills in retirement, esp as I 'age out', and Best Comfort Possible: the TT boiler gives me really warm floors upstairs and ceilings below, which for me is a true LUXURY, and The Best Heat Ever (and no damned set-back or fancy smart Tstats either!)
If I were starting from scratch today, I'd go with a super high efficiency gas boiler for DHW and heat, plus PV for electricity.
