ess
New Member
Hi - I've been lurking on this forum quite a bit gathering all sorts of tips on boilers, insulation, etc. etc., and I was hoping that if I posted my situation, I might be able to get some of the great advice as well.
Summary: We have an newish but kind of mediocre boiler, and I'm trying to determine if it's worth improving the current boiler or taking the money that we would put into the existing boiler and putting it towards a new (better) one.
[House]
- Location: North of Boston (01810)
- Family of 6 (4 adults, 2 children)
- House built 1968; 2 story colonial with mostly "finished" basement, ~1500 square feet / floor (I believe the deed has us around 3200 not counting the basement)
- Blower door test: 4202 cfm50 (mid-high, but that's down from 6200 before MassSave air sealing!)
- Blown in cellulose in attic floor and eaves; mostly (but not all) replacement windows; basement heated but almost certainly not well insulated (on our plan for before winter); 1960s insulated walls (fiberglass; IR tests seem to show that it's mostly still there and hopefully helping a bit)
- We installed a Carrier Greenspeed (ducted) heat pump last winter/spring in the attic for the second floor to help with non-design day heating (at least for the 2nd floor zone) and provide summer cooling.
- We tend to keep the house on the cool side - 68 is about max for us, and I think our setbacks go as low as 62.
[Boiler]
Hydrotherm PB-105-WT boiler, installed probably about 3.5 years ago (not by us) and currently used only for heat
http://www.drillspot.com/products/51168/hydrotherm_pb105_120w_water_oil_fired_boiler
Beckett 7505 GeniSys Control; Watts Model ETX-30 Pressurized Expansion Tank with Diaphragm
0.65 x 80A @ 140 PS Nozzle = 0.77 GPH
Rated ~85% new; Latest combustion test: 82%
Three zones (2nd floor, 1st floor, basement)
- The boiler is in an unheated garage room (boiler definitely warms it up).
- Fin tube baseboard radiators (some in less than stellar condition). Upstairs heat has a lot of pinging, banging and clicking sounds that may be due to badly installed baseboard (missing dampening pieces?) or damage (fins touching each other) or...something else.
- Rooms far from the thermostat on the second floor are quite cold, although we do have issues with the thermostat being placed incorrectly (all the way at the other end of the house) / damaged baseboards / furniture probably interfering, so I'm thinking that it's more of a repair issue than an issue with the boiler itself. I checked and the pipes for the baseboard in one of the cold rooms do get warm / hot (although not burning to the touch immediately). That seems to have ruled out air in the pipes (I think?), although I've been meaning to check and see if individual baseboards have bleed valves (I'm guessing unlikely).
[Energy use]
I have tried my best to do a bunch of the necessary calculations, but I'm not sure I've done them 100% correctly.
We use about 1000 gallons of oil per year overall; the numbers here are a bit lower because I was trying to match up the degree days to oil deliveries.
Closest degree days station: Osgood Street, Andover, MA (71.19W,42.63N) KMAANDOV3
For 10/1/12 - 5/30/13, I got:
Heating Degree Days: 6034
Oil usage: ~845.7 (we got a delivery of 108.5 gallons on 5/23, but I kept the 10/3/12 delivery of 21 gallons...it's not perfect)
Calculated K-Factor: 7.13 (this is my number - our oil company does not provide on invoices)
BTU / hour @ 80% = 41907
BTU / hour @ 85% = 44526
For the calculations I made during 11/01/13 - 01/31/14:
Heating Degree Days: 3213
Oil usage: ~534.4
Calculated K-Factor: 6.01 (this is my number, same as above)
BTU / hour @ 80% = 49730
BTU / hour @ 85% = 52839
Is this showing that the boiler is oversized for our heating needs (about 2x, give or take)? Especially considering that it is feeding three separate zones and doesn't modulate?
Basically, I'm trying to figure out if it would be overkill to spend a lot of money to upgrade the current boiler to something right-sized and efficient, like an Energy Kinetics or Firebird boiler. If we can get ROI even within 10-15 years, I could see a point, but it's unclear to me how much we could expect to save each year (we might need to save like 30%), especially since we're hoping to lower some of the energy costs via the new heat pump.
This is made a little more complicated by the fact that with the current boiler, there are some changes to be made (see below - chimney, heat purge control, possible hot water tank, etc.), so we'll be spending money on the heating system either way. It might be that the true difference between improving / fixing the current system and installing a new one is more like half of the full upgrade cost (and thus a much easier ROI), but that depends on which fixes would be worth making on the current boiler.
For potential replacements, I've been looking at Energy Kinetics EK1 and Buderus G125be, and I saw a Firebird boiler mentioned as well. The smallest available appear to be around 80k BTU / hr - so closer to estimated heat load range, but not -that- much better than what we have now (about 15%?).
[Questions]
1) Thoughts on whether the better sizing and benefits (integrated smart controls, better venting, better insulation, etc.) are worth the rather steep upgrade cost versus retrofitting the current boiler? Is the current boiler worth improving? I keep thinking that it's only 3ish years old, so I'd hate to rip it out, but it really does seem mediocre when compared to what else is out there.
2) Our current electric hot water heater likely is the reason why our electric bill is higher than we'd like, plus it's about 18 years old and we do run out of hot water with multiple serial showers. I've been very happy with indirect hot water in the past, but since our boiler isn't that efficient (and oil is expensive), would we be better off getting a heat pump / electric hot water tank (maybe oversizing it a little if we're worried about capacity)? Is this mitigated by indirect hot water heaters being so efficient at holding temp?
(For the heat pump hot water heater, are there any that you'd recommend that are quieter and/or more efficient / reliable than most? The current hot water heater is located fairly near the basement recreation room, so having extra noise down there didn't seem like a great thing.)
If we went with the indirect option, would we be able to cold start the existing boiler, or would it need to run all the time (warm start?) - and if the latter, would there be a lot of extra oil used over the summer?
3) We currently have a powervent out the side of the house that is somewhat smelly (slight burning oil smell - we've been told this is normal?) and in a location that's close enough to an inside corner / porch that we want to move it. The suggestion from the oil company representative was to install a double-wall insulated stainless flue (we can go straight up through the roof of the garage). I'm a little concerned about chimney draft hurting the already mediocre efficiency of the boiler, but it does seem to be the only other option, assuming we stay with the current boiler. Does the chimney sound okay, or is this another reason to consider a new boiler that might be able to vent more efficiently?
4) Are there cheaper upgrades that we could make to the current system that would help efficiency as well as fix the comfort / coldness issues (assuming we find someone qualified who will actually look at the baseboards)? Would that potentially make it worthwhile to consider an indirect hot water tank instead of the heat pump?
Some of the items I've been considering - which of these would you recommend, or are there others you would suggest?
- Intellicon HW+ or other heat purge control (am I correct that this would work better for us than an outdoor reset, since the temp needs to stay about 140 anyway?)
- Thermostats that can interact and coordinate zone calls
--I have no idea if the boiler is short-cycling - I definitely don't think it's running all the time. I'm assuming combining zone calls would help, but is there anything else that can be done?
- Insulate the boiler plumbing, or the boiler itself (or at least add insulation to the boiler "room")
- Stop using setbacks as much (don't use them at all?)
- Slow close zone valves? Variable speed circulator pump? I think one of these was suggested as potentially helping with the pipe / baseboard noises (by the oil company assessor).
5) We're considering adding heat to our 3-season porch - ideally radiant (in-floor), although we have other options. We'd have to add another zone to the existing boiler to do so. Is the efficiency of the current boiler low enough and/or would the radiant zone be so small (as the boiler doesn't modulate) that we should consider something else (pellet stove, ductless unit, etc.)?
Also, I would be very grateful to receive any HVAC contractor recommendations in my area (via PM), especially ones familiar with retrofitting oil boilers.
Thank you so much!
Summary: We have an newish but kind of mediocre boiler, and I'm trying to determine if it's worth improving the current boiler or taking the money that we would put into the existing boiler and putting it towards a new (better) one.
[House]
- Location: North of Boston (01810)
- Family of 6 (4 adults, 2 children)
- House built 1968; 2 story colonial with mostly "finished" basement, ~1500 square feet / floor (I believe the deed has us around 3200 not counting the basement)
- Blower door test: 4202 cfm50 (mid-high, but that's down from 6200 before MassSave air sealing!)
- Blown in cellulose in attic floor and eaves; mostly (but not all) replacement windows; basement heated but almost certainly not well insulated (on our plan for before winter); 1960s insulated walls (fiberglass; IR tests seem to show that it's mostly still there and hopefully helping a bit)
- We installed a Carrier Greenspeed (ducted) heat pump last winter/spring in the attic for the second floor to help with non-design day heating (at least for the 2nd floor zone) and provide summer cooling.
- We tend to keep the house on the cool side - 68 is about max for us, and I think our setbacks go as low as 62.
[Boiler]
Hydrotherm PB-105-WT boiler, installed probably about 3.5 years ago (not by us) and currently used only for heat
http://www.drillspot.com/products/51168/hydrotherm_pb105_120w_water_oil_fired_boiler
Beckett 7505 GeniSys Control; Watts Model ETX-30 Pressurized Expansion Tank with Diaphragm
0.65 x 80A @ 140 PS Nozzle = 0.77 GPH
Rated ~85% new; Latest combustion test: 82%
Three zones (2nd floor, 1st floor, basement)
- The boiler is in an unheated garage room (boiler definitely warms it up).
- Fin tube baseboard radiators (some in less than stellar condition). Upstairs heat has a lot of pinging, banging and clicking sounds that may be due to badly installed baseboard (missing dampening pieces?) or damage (fins touching each other) or...something else.
- Rooms far from the thermostat on the second floor are quite cold, although we do have issues with the thermostat being placed incorrectly (all the way at the other end of the house) / damaged baseboards / furniture probably interfering, so I'm thinking that it's more of a repair issue than an issue with the boiler itself. I checked and the pipes for the baseboard in one of the cold rooms do get warm / hot (although not burning to the touch immediately). That seems to have ruled out air in the pipes (I think?), although I've been meaning to check and see if individual baseboards have bleed valves (I'm guessing unlikely).
[Energy use]
I have tried my best to do a bunch of the necessary calculations, but I'm not sure I've done them 100% correctly.
We use about 1000 gallons of oil per year overall; the numbers here are a bit lower because I was trying to match up the degree days to oil deliveries.
Closest degree days station: Osgood Street, Andover, MA (71.19W,42.63N) KMAANDOV3
For 10/1/12 - 5/30/13, I got:
Heating Degree Days: 6034
Oil usage: ~845.7 (we got a delivery of 108.5 gallons on 5/23, but I kept the 10/3/12 delivery of 21 gallons...it's not perfect)
Calculated K-Factor: 7.13 (this is my number - our oil company does not provide on invoices)
BTU / hour @ 80% = 41907
BTU / hour @ 85% = 44526
For the calculations I made during 11/01/13 - 01/31/14:
Heating Degree Days: 3213
Oil usage: ~534.4
Calculated K-Factor: 6.01 (this is my number, same as above)
BTU / hour @ 80% = 49730
BTU / hour @ 85% = 52839
Is this showing that the boiler is oversized for our heating needs (about 2x, give or take)? Especially considering that it is feeding three separate zones and doesn't modulate?
Basically, I'm trying to figure out if it would be overkill to spend a lot of money to upgrade the current boiler to something right-sized and efficient, like an Energy Kinetics or Firebird boiler. If we can get ROI even within 10-15 years, I could see a point, but it's unclear to me how much we could expect to save each year (we might need to save like 30%), especially since we're hoping to lower some of the energy costs via the new heat pump.
This is made a little more complicated by the fact that with the current boiler, there are some changes to be made (see below - chimney, heat purge control, possible hot water tank, etc.), so we'll be spending money on the heating system either way. It might be that the true difference between improving / fixing the current system and installing a new one is more like half of the full upgrade cost (and thus a much easier ROI), but that depends on which fixes would be worth making on the current boiler.
For potential replacements, I've been looking at Energy Kinetics EK1 and Buderus G125be, and I saw a Firebird boiler mentioned as well. The smallest available appear to be around 80k BTU / hr - so closer to estimated heat load range, but not -that- much better than what we have now (about 15%?).
[Questions]
1) Thoughts on whether the better sizing and benefits (integrated smart controls, better venting, better insulation, etc.) are worth the rather steep upgrade cost versus retrofitting the current boiler? Is the current boiler worth improving? I keep thinking that it's only 3ish years old, so I'd hate to rip it out, but it really does seem mediocre when compared to what else is out there.
2) Our current electric hot water heater likely is the reason why our electric bill is higher than we'd like, plus it's about 18 years old and we do run out of hot water with multiple serial showers. I've been very happy with indirect hot water in the past, but since our boiler isn't that efficient (and oil is expensive), would we be better off getting a heat pump / electric hot water tank (maybe oversizing it a little if we're worried about capacity)? Is this mitigated by indirect hot water heaters being so efficient at holding temp?
(For the heat pump hot water heater, are there any that you'd recommend that are quieter and/or more efficient / reliable than most? The current hot water heater is located fairly near the basement recreation room, so having extra noise down there didn't seem like a great thing.)
If we went with the indirect option, would we be able to cold start the existing boiler, or would it need to run all the time (warm start?) - and if the latter, would there be a lot of extra oil used over the summer?
3) We currently have a powervent out the side of the house that is somewhat smelly (slight burning oil smell - we've been told this is normal?) and in a location that's close enough to an inside corner / porch that we want to move it. The suggestion from the oil company representative was to install a double-wall insulated stainless flue (we can go straight up through the roof of the garage). I'm a little concerned about chimney draft hurting the already mediocre efficiency of the boiler, but it does seem to be the only other option, assuming we stay with the current boiler. Does the chimney sound okay, or is this another reason to consider a new boiler that might be able to vent more efficiently?
4) Are there cheaper upgrades that we could make to the current system that would help efficiency as well as fix the comfort / coldness issues (assuming we find someone qualified who will actually look at the baseboards)? Would that potentially make it worthwhile to consider an indirect hot water tank instead of the heat pump?
Some of the items I've been considering - which of these would you recommend, or are there others you would suggest?
- Intellicon HW+ or other heat purge control (am I correct that this would work better for us than an outdoor reset, since the temp needs to stay about 140 anyway?)
- Thermostats that can interact and coordinate zone calls
--I have no idea if the boiler is short-cycling - I definitely don't think it's running all the time. I'm assuming combining zone calls would help, but is there anything else that can be done?
- Insulate the boiler plumbing, or the boiler itself (or at least add insulation to the boiler "room")
- Stop using setbacks as much (don't use them at all?)
- Slow close zone valves? Variable speed circulator pump? I think one of these was suggested as potentially helping with the pipe / baseboard noises (by the oil company assessor).
5) We're considering adding heat to our 3-season porch - ideally radiant (in-floor), although we have other options. We'd have to add another zone to the existing boiler to do so. Is the efficiency of the current boiler low enough and/or would the radiant zone be so small (as the boiler doesn't modulate) that we should consider something else (pellet stove, ductless unit, etc.)?
Also, I would be very grateful to receive any HVAC contractor recommendations in my area (via PM), especially ones familiar with retrofitting oil boilers.
Thank you so much!