neilly2
Silver Member
Is anybody an HVAC pro? I'm halfway through building the new house and have some key questions mostly basics, before I let out the contract on the heat and air.
HVAC Experts
- Thread starter neilly2
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BarryinMN
Platinum Member
Birdhunter1
Veteran Member
What's your question. I used to do it a few years ago.
Ray2210
Silver Member
Ask your questions. Any of us with Mechanical Engineering backgrounds can answer some of them, others may require a contractors advice.
ronjhall
Super Star Member
Here is a thread from last fall that help with HVAC decision's. Click Here
You may want to PM some of the posters in the thread.
You may want to PM some of the posters in the thread.
Scozz
Silver Member
Fire away .. send me a PM if you like. I've been in the HVAC field for 25 years now .. glad to help if I can ... Scozz
I'll be installing hydronic baseboard heat, LP fired boiler, and central AC. I would like to go as efficient as possible without wasting the upfront cost.
I've been researching pretty hard and I think I'm burnt out. I think I've learned that the HVAC systems are a little like tractors. Each person has different company loyalties based on their own experience, different requirements based on their geography, their are a few good names of equipment that are essentially equal, you should be most concerned with availability of service, and the more you spend the more you get.
1. For the AC one contractor insists that one larger unit with zone control by dampers is the better way to go then 2 separate smaller units. This goes against what most people have around here.
2. One bidder insists the upfront cost for the high end 16 or 19 SEER Trane or Carrier units is worth it. Any idea on the differential cost going from a 14 to a 19.5 SEER?
3. What activates cycling between stages in a 2 stage compressor? Is the compressor stage controlled strictly by cooling demand? Does outside air temp play into it?
4. Boiler -- I am leaning towards a high EFF. condensing boiler, but someone has recommended a conventional boiler with low temp baseboard to accomplish a similar efficiency. This one really has me cornfused.
5. As far as the condensing boiler, the consensus seems to be you can't lose with : Buderus,Veissman, or Peerless. Specifically the Veismann is top notch, but people say the cost is ridiculus, but I have no idea what the cost of one of those is. Those 3 units never seem to have a bad word said about them. Next would be Weil-McClain which people seem to either love or hate. (same reaction that grey market tractors get)
6. I was anticipating a hydronic towel warmer to heat the master bath since we won't have wall space for baseboard. Comments???
7. We may have to go with fan powered hydronic toe kick heaters in the kitchen. I hate the sound of fans blowing. Any idea of the sound rating on these things?
8. I'm anticipating an outside air intake with heat exchanger, since I went and sealed the house up like a zip lock bag without thinking ahead. Any problems to look for with this.
9. Heat will have three zones, AC two.
10. Hot water will be indirect tank, separate zone off of boiler.
11. I'm kicking around the idea of underfloor radiant in the kitchen to get rid of the toe space heater, but that might pinch the budget. Would that be a second loop off of the hot water heater? The boiler water temp would be to hot.
12. I would love to be able to afford that $5000 heated toilet.
14. I will only install sheetmetal duct as opposed to the fiberglass board.
15. Everyone is quoting 5 thermostats (2 AC, 3 Heat). Isn't their a stat or controller that can control the heat and A/C both in the common zone?
Any thoughts or comments are appreciated.
I've been researching pretty hard and I think I'm burnt out. I think I've learned that the HVAC systems are a little like tractors. Each person has different company loyalties based on their own experience, different requirements based on their geography, their are a few good names of equipment that are essentially equal, you should be most concerned with availability of service, and the more you spend the more you get.
1. For the AC one contractor insists that one larger unit with zone control by dampers is the better way to go then 2 separate smaller units. This goes against what most people have around here.
2. One bidder insists the upfront cost for the high end 16 or 19 SEER Trane or Carrier units is worth it. Any idea on the differential cost going from a 14 to a 19.5 SEER?
3. What activates cycling between stages in a 2 stage compressor? Is the compressor stage controlled strictly by cooling demand? Does outside air temp play into it?
4. Boiler -- I am leaning towards a high EFF. condensing boiler, but someone has recommended a conventional boiler with low temp baseboard to accomplish a similar efficiency. This one really has me cornfused.
5. As far as the condensing boiler, the consensus seems to be you can't lose with : Buderus,Veissman, or Peerless. Specifically the Veismann is top notch, but people say the cost is ridiculus, but I have no idea what the cost of one of those is. Those 3 units never seem to have a bad word said about them. Next would be Weil-McClain which people seem to either love or hate. (same reaction that grey market tractors get)
6. I was anticipating a hydronic towel warmer to heat the master bath since we won't have wall space for baseboard. Comments???
7. We may have to go with fan powered hydronic toe kick heaters in the kitchen. I hate the sound of fans blowing. Any idea of the sound rating on these things?
8. I'm anticipating an outside air intake with heat exchanger, since I went and sealed the house up like a zip lock bag without thinking ahead. Any problems to look for with this.
9. Heat will have three zones, AC two.
10. Hot water will be indirect tank, separate zone off of boiler.
11. I'm kicking around the idea of underfloor radiant in the kitchen to get rid of the toe space heater, but that might pinch the budget. Would that be a second loop off of the hot water heater? The boiler water temp would be to hot.
12. I would love to be able to afford that $5000 heated toilet.
14. I will only install sheetmetal duct as opposed to the fiberglass board.
15. Everyone is quoting 5 thermostats (2 AC, 3 Heat). Isn't their a stat or controller that can control the heat and A/C both in the common zone?
Any thoughts or comments are appreciated.
Birdhunter1
Veteran Member
Why would you want to go with a boiler?
Seriously if your house is sealed up like a Ziploc bag and you're looking at actually needing a fresh air intake system you are an ideal candidate for a geothermal system.
Geothermal will work in any climate efficiently as long as the house is sealed up tight and insulated well, which it sounds as if yours is.
Geothermal costs will nto be more expensive than a zoned boiler system AND a zoned A/C system or 2 a/c system.
Good call on the sheetmetal duct, make sure and use it on the round piping (from the truck line ot the registers) as well instead of flexible duct!
Seriously if your house is sealed up like a Ziploc bag and you're looking at actually needing a fresh air intake system you are an ideal candidate for a geothermal system.
Geothermal will work in any climate efficiently as long as the house is sealed up tight and insulated well, which it sounds as if yours is.
Geothermal costs will nto be more expensive than a zoned boiler system AND a zoned A/C system or 2 a/c system.
Good call on the sheetmetal duct, make sure and use it on the round piping (from the truck line ot the registers) as well instead of flexible duct!
RE: 2. One bidder insists the upfront cost for the high end 16 or 19 SEER Trane or Carrier units is worth it. Any idea on the differential cost going from a 14 to a 19.5 SEER?
The operating cost will be roughly proportional to the inverse of the ratings. The 14 SEER unit will require about 50% more electricity to run than the 19.5 SEER for the same cooling load. If your air conditioning is $100 per month with the 19.5 SEER, it will be about $150 with the 14 SEER. If the 19.5 SEER system costs $1000 more, it will take 20 months of cooling to make up that cost differential (with the above numbers).
This assumes an ideal installation and conditions that match the test conditions. As they, "your actual mileage may vary".
RE: 3. What activates cycling between stages in a 2 stage compressor? Is the compressor stage controlled strictly by cooling demand? Does outside air temp play into it?
I would think that you need a 2-stage capable control system or thermostat to activate the two stages, but it may be that the air handler can do the control based on an internal algorithm based on how long the T-stat calls for cooling.
4. Boiler Temp
You can add an inxepensive tempering / mixing valve or a more sophisticated mixing system to generate lower temp water out of a higher temp boiler. A Reset controller can also cycle the boiler to any desired temp, assuming the boiler is a condensing unit, it won't care. Some control system run the boiler at one temp when a radiant or baseboard zone demand heat and another temp for higher-temp zones like indirect hot water production.
5. Boiler
I have a Carrier condensing Boiler that I am very happy with. I think its actually made by Dunkirk.
RE: 6. I was anticipating a hydronic towel warmer to heat the master bath since we won't have wall space for baseboard. Comments???
I considered a heated towel bar in our bathroom, but with the under-floor radiant, forced air, and gas fireplace in there, it gets warm enough!
RE: 8. I'm anticipating an outside air intake with heat exchanger, since I went and sealed the house up like a zip lock bag without thinking ahead. Any problems to look for with this.
I think this is required by code these days.
The operating cost will be roughly proportional to the inverse of the ratings. The 14 SEER unit will require about 50% more electricity to run than the 19.5 SEER for the same cooling load. If your air conditioning is $100 per month with the 19.5 SEER, it will be about $150 with the 14 SEER. If the 19.5 SEER system costs $1000 more, it will take 20 months of cooling to make up that cost differential (with the above numbers).
This assumes an ideal installation and conditions that match the test conditions. As they, "your actual mileage may vary".
RE: 3. What activates cycling between stages in a 2 stage compressor? Is the compressor stage controlled strictly by cooling demand? Does outside air temp play into it?
I would think that you need a 2-stage capable control system or thermostat to activate the two stages, but it may be that the air handler can do the control based on an internal algorithm based on how long the T-stat calls for cooling.
4. Boiler Temp
You can add an inxepensive tempering / mixing valve or a more sophisticated mixing system to generate lower temp water out of a higher temp boiler. A Reset controller can also cycle the boiler to any desired temp, assuming the boiler is a condensing unit, it won't care. Some control system run the boiler at one temp when a radiant or baseboard zone demand heat and another temp for higher-temp zones like indirect hot water production.
5. Boiler
I have a Carrier condensing Boiler that I am very happy with. I think its actually made by Dunkirk.
RE: 6. I was anticipating a hydronic towel warmer to heat the master bath since we won't have wall space for baseboard. Comments???
I considered a heated towel bar in our bathroom, but with the under-floor radiant, forced air, and gas fireplace in there, it gets warm enough!
RE: 8. I'm anticipating an outside air intake with heat exchanger, since I went and sealed the house up like a zip lock bag without thinking ahead. Any problems to look for with this.
I think this is required by code these days.
5030tinkerer
Gold Member
Re: 8. You might want to check out the article here from concrete network. Item #10 talks about a ventilation on demand system in lieu of a conventional air exchanger. Interesting stuff, at least to me. /forums/images/graemlins/grin.gif
Scozz
Silver Member
Well .. I just spent about an hour typing responses to all 15 ?'s adn lost it when I clicked spell check .. /forums/images/graemlins/mad.gif
Lets try again .. probably will be more brief this time though!
1. One zone or two? Depends on the size of the home, size of the zones and you budget. If its a very large home requiring over 4 tons of cooling you can cut energy costs by installing two systems and runnning only when needed. Zoning can be tricky and I've seen MANY more poorly installed zone systems then good ones. To operate well zones should be as close to 50/50 in load as possible. Ductwork to each zone should be oversized 25% to accomodate for when on e zone is closed. If the load is unproportaional (75/25 or so) then bypass duct, dump zone and/or freeze stat must be installed to prevent freeze-ups.
2. In my area of NY we have short coooling seasons (3 months or so) with days over 100* normally counted on one hand. There is no reteun on investment going to a two stage unit (used on 18+ SEER units) in my area. It generall costs $2000 additional for such an upgrade and it will not return in the life of teh equipment. AS of 1/1/06 the minimum SEER has been raised from 10 SEER to 13 SEER. Supopliers may no longer sell anything below 13SEER once they have depleated old stock. If you have long cooling season and expensive electricity it may be worth looking into.
3.A two stage thermostat is used to stage compressors.
Benefit of two stage unit is ablility to ad a humidistat and run in "dehumidify" mode
4. buy the most efficient boiler you can swing.. you can still add a temperature compensating control to drop boiler water temp and gain more efficiency. Ther is something to be said for the 80% boilers if fuel is cheap in your area (KISS theory) 80% boilers ternd to have less maintainence issues.
5. Buderus is the boiler of my choice. They make a new wall hung unit that is the cats meow ..although pricey! WeilMclean mades an adequate gas boiler (although I deplore the Gold series oil boilers the older blue series were much better) comparign the two is apples to bannanas though.
6.Towel warmers kick a@$!! I have one in my master bath. You will probaly have to add a mixing valve to drop the water temp to it though 180* water will burn you if you touch the warmer. Min is VERY hot ... I run 165* water thru mine and it is very hot (my whole house is high temperature radiant heat)
7. Some kick heaters have 3 speed fans .. If you but a unit larger than required and run it at low speed it sould not be tto noisey ... GO FOR THE RADIANT IF YOU CAN SWING IT!!! You'll be sorry you did not do the entire house if you do!!
8. I've anly installed one fresh air unit in my life! I have little expertise to offer here.
9. Zoning a hydraunic unit is easy ... don't sell yourself short. May sure any area the may have "different" use is a seprate zone (Living area, formal dinind room, MBR, other BR, Bonus room over garage, basement, garage, etc).
10. You'll be very happy with an indirect6 HWH.. I have an Amtrol 40 Gal and have never run out of HW> Make sure your boiler is large enough to give you adequate capacity. I'm in oil heat territory and we can fire up the boiler easily just bey changing the nozzle. If you'r running a small boiler (under 100K) you may want to connsider an instantainuos water heater (rinai makes a great unit) which will also produce unlimited HW with not storage.
11. You'd have to drop the boiler water temp with a thermostatic bypass valve or a tempering valve (as mantioned previously). The valve mixes return water to the boiler with the supply water to the loop to drop the temperature. Depending on your construcion and radiant intall you may not have to drop the water temop too much. I have about 3600 sqft of staple up to the sub floortubing with reflective insulation below heting first and secondfloor. I have about 2600 sqft of basementy slab also heated. (over 10,000 feet of tubing) I rarely turn the basement on though ... its just plaly area for my children right now and it sucks up the oil when its running. I run my pex loops at 165* which is on the high end for radiant.
12. Theres lots of things I wish I coud afford ... heated toilet is not high on the list though /forums/images/graemlins/grin.gif
13. Skipped number just like a hotel!!
14. I too will only use sheetmetal duct systems. . I've removed too many duct board plenums that have deteriorated after years of use/abuse.
15. Yes, you can put heat/cool on one stat. The stat must have seperate cicrcuits for each. Most digital stats can accomodate this. There is a jumper between Rc and Rh that must be removed. This created two isolated circuits in the stat so that the transformers from teh boiler and air handler do not buck.
Lastly .. don't sell yourself short on teh comfort system ... you'll be living with the results for a lonf time. If possible look into a variable speed airhandler for the A/C...you'll be happy if you do choose such a system. The variable speed blower gradually ramps up to speed and down. the result is a sub-cooled col that removes 1/3 more himidity. It will usually add 1 SEER to a system. It also runs at 50% of full speed when the fan is in the on position and there is no call for cooling. It will filter very efficiently (buy a goood filter I use Spacegard) with reduced speed and only uses 60 watts of electric vrs. 4-600 watt that a convenetinal blower uses. Most of teh systems I install are variable speed. That upgrade is only several hundred dollars. ... Good luck ... Scozz
Lets try again .. probably will be more brief this time though!
1. One zone or two? Depends on the size of the home, size of the zones and you budget. If its a very large home requiring over 4 tons of cooling you can cut energy costs by installing two systems and runnning only when needed. Zoning can be tricky and I've seen MANY more poorly installed zone systems then good ones. To operate well zones should be as close to 50/50 in load as possible. Ductwork to each zone should be oversized 25% to accomodate for when on e zone is closed. If the load is unproportaional (75/25 or so) then bypass duct, dump zone and/or freeze stat must be installed to prevent freeze-ups.
2. In my area of NY we have short coooling seasons (3 months or so) with days over 100* normally counted on one hand. There is no reteun on investment going to a two stage unit (used on 18+ SEER units) in my area. It generall costs $2000 additional for such an upgrade and it will not return in the life of teh equipment. AS of 1/1/06 the minimum SEER has been raised from 10 SEER to 13 SEER. Supopliers may no longer sell anything below 13SEER once they have depleated old stock. If you have long cooling season and expensive electricity it may be worth looking into.
3.A two stage thermostat is used to stage compressors.
Benefit of two stage unit is ablility to ad a humidistat and run in "dehumidify" mode
4. buy the most efficient boiler you can swing.. you can still add a temperature compensating control to drop boiler water temp and gain more efficiency. Ther is something to be said for the 80% boilers if fuel is cheap in your area (KISS theory) 80% boilers ternd to have less maintainence issues.
5. Buderus is the boiler of my choice. They make a new wall hung unit that is the cats meow ..although pricey! WeilMclean mades an adequate gas boiler (although I deplore the Gold series oil boilers the older blue series were much better) comparign the two is apples to bannanas though.
6.Towel warmers kick a@$!! I have one in my master bath. You will probaly have to add a mixing valve to drop the water temp to it though 180* water will burn you if you touch the warmer. Min is VERY hot ... I run 165* water thru mine and it is very hot (my whole house is high temperature radiant heat)
7. Some kick heaters have 3 speed fans .. If you but a unit larger than required and run it at low speed it sould not be tto noisey ... GO FOR THE RADIANT IF YOU CAN SWING IT!!! You'll be sorry you did not do the entire house if you do!!
8. I've anly installed one fresh air unit in my life! I have little expertise to offer here.
9. Zoning a hydraunic unit is easy ... don't sell yourself short. May sure any area the may have "different" use is a seprate zone (Living area, formal dinind room, MBR, other BR, Bonus room over garage, basement, garage, etc).
10. You'll be very happy with an indirect6 HWH.. I have an Amtrol 40 Gal and have never run out of HW> Make sure your boiler is large enough to give you adequate capacity. I'm in oil heat territory and we can fire up the boiler easily just bey changing the nozzle. If you'r running a small boiler (under 100K) you may want to connsider an instantainuos water heater (rinai makes a great unit) which will also produce unlimited HW with not storage.
11. You'd have to drop the boiler water temp with a thermostatic bypass valve or a tempering valve (as mantioned previously). The valve mixes return water to the boiler with the supply water to the loop to drop the temperature. Depending on your construcion and radiant intall you may not have to drop the water temop too much. I have about 3600 sqft of staple up to the sub floortubing with reflective insulation below heting first and secondfloor. I have about 2600 sqft of basementy slab also heated. (over 10,000 feet of tubing) I rarely turn the basement on though ... its just plaly area for my children right now and it sucks up the oil when its running. I run my pex loops at 165* which is on the high end for radiant.
12. Theres lots of things I wish I coud afford ... heated toilet is not high on the list though /forums/images/graemlins/grin.gif
13. Skipped number just like a hotel!!
14. I too will only use sheetmetal duct systems. . I've removed too many duct board plenums that have deteriorated after years of use/abuse.
15. Yes, you can put heat/cool on one stat. The stat must have seperate cicrcuits for each. Most digital stats can accomodate this. There is a jumper between Rc and Rh that must be removed. This created two isolated circuits in the stat so that the transformers from teh boiler and air handler do not buck.
Lastly .. don't sell yourself short on teh comfort system ... you'll be living with the results for a lonf time. If possible look into a variable speed airhandler for the A/C...you'll be happy if you do choose such a system. The variable speed blower gradually ramps up to speed and down. the result is a sub-cooled col that removes 1/3 more himidity. It will usually add 1 SEER to a system. It also runs at 50% of full speed when the fan is in the on position and there is no call for cooling. It will filter very efficiently (buy a goood filter I use Spacegard) with reduced speed and only uses 60 watts of electric vrs. 4-600 watt that a convenetinal blower uses. Most of teh systems I install are variable speed. That upgrade is only several hundred dollars. ... Good luck ... Scozz
Farwell
Veteran Member
The spell checker has cost me several lost posts so I got wise, if I do any long posts I do them in a word processor, spell check them there, then copy and paste them on the TBN site. Most of the posts I lost I do not re-type due to frustration.
Farwell
Farwell
Wow... thanks for the replies guys! Its really starting to fill in some of the dark areas of my brain when its comes to the systems.
I'd like to see a pic of the bathroom with a fireplace in it.
I'm following both pieces of advise on the boiler and it will be the wall hung high eff. unit.
I definitely will be going with a variable speed AHU.
Out of curiosity, when you had to replace the fiberglass duct, was it physically damaged from the outside or was it deteriorating on the inside. I just can't see sending my breathing air across fiberglass, no matter how treated it is. I also heard California will be outlawing this stuff shortly.
I forgot to mention the indirect fired water heater. Its a non issue since my brother in law is a sales rep for Bradford White. I wish BW just bought Buderus instead of LAARS!
I'm still torn on the 1 AC unit vs. 2 vs. high eff. vs. low eff. I'll do some more research.
Any recommendations on stats. I seem to not think about it and it probably makes a difference.
I'd like to see a pic of the bathroom with a fireplace in it.
I'm following both pieces of advise on the boiler and it will be the wall hung high eff. unit.
I definitely will be going with a variable speed AHU.
Out of curiosity, when you had to replace the fiberglass duct, was it physically damaged from the outside or was it deteriorating on the inside. I just can't see sending my breathing air across fiberglass, no matter how treated it is. I also heard California will be outlawing this stuff shortly.
I forgot to mention the indirect fired water heater. Its a non issue since my brother in law is a sales rep for Bradford White. I wish BW just bought Buderus instead of LAARS!
I'm still torn on the 1 AC unit vs. 2 vs. high eff. vs. low eff. I'll do some more research.
Any recommendations on stats. I seem to not think about it and it probably makes a difference.
Scozz
Silver Member
Most of the fiberglass duct failures I've dealt with were due to "abuse". Duct systems in an attic that people had used for storage. Over the years they colapsed the ducts. With regards the Tstats ... keep it simple. Some of the more sophisticated 7 day programable models take a computer engineering degree to figure out and wind up just being set on "hold temp" to defeat the programing that the customer cannot figure out. Get a simple 5/2 day (I use the White Rogers) they are cheap, easy to program and dependable....Scozz
T-stats:
I went nerdy on my thermostats.
I used the Carrier 4-zone system for the forced air portions of my house. Its full featured as far as forced air heating, cooling, zone-dampers, and humidity control goes. Can run a variable speed air handler and/or multi-speed compressor AC. I don't think it can do two AC units. Lots of programming bells and whistles.
My wife can only deal with the manual override which is accessed with two big buttons on the outside of the units. All the fancy programming is under covers. I think they have a new model out now.
I used Tekmar 500-series units for the hydronic zones. I know that they had units that could do heating and cooling in the same room, including multi-stage heating and/or multi-stage cooling. Many of their units are tailored for the slower response times of hydronic slab heating and have min and max slab temp control (using slab temp sensor) as well as room air temp control.
The Tekmars are even more nerdy to program, but they are very small and look nice on the wall.
Tekmar also makes some centralized multi-zone systems.
I used a simple Taco relay box to switch the zone pumps (and Taco pumps). Their six-zone box had a boiler-reset / low-temp mixing control option and indirect hot water priority functions that were perfect for my setup.
Shop around for prices on the Taco and Tekmar stuff - I found about a 2X difference between the high and low prices on these items on the web.
Both Tekmar and Taco have excellent technical info on their websites.
- Rick
I went nerdy on my thermostats.
I used the Carrier 4-zone system for the forced air portions of my house. Its full featured as far as forced air heating, cooling, zone-dampers, and humidity control goes. Can run a variable speed air handler and/or multi-speed compressor AC. I don't think it can do two AC units. Lots of programming bells and whistles.
My wife can only deal with the manual override which is accessed with two big buttons on the outside of the units. All the fancy programming is under covers. I think they have a new model out now.
I used Tekmar 500-series units for the hydronic zones. I know that they had units that could do heating and cooling in the same room, including multi-stage heating and/or multi-stage cooling. Many of their units are tailored for the slower response times of hydronic slab heating and have min and max slab temp control (using slab temp sensor) as well as room air temp control.
The Tekmars are even more nerdy to program, but they are very small and look nice on the wall.
Tekmar also makes some centralized multi-zone systems.
I used a simple Taco relay box to switch the zone pumps (and Taco pumps). Their six-zone box had a boiler-reset / low-temp mixing control option and indirect hot water priority functions that were perfect for my setup.
Shop around for prices on the Taco and Tekmar stuff - I found about a 2X difference between the high and low prices on these items on the web.
Both Tekmar and Taco have excellent technical info on their websites.
- Rick
