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I have a couple of questions for the group in connection with a sizeable addition project in Minnesota (the addition is approximately 2400 square feet).
b Background.
We are installing hydronic heating in the addition. The total heating load for the first and second floor is approximately 62,000 Btus. Most of this is addressed with ½” PEX in Warmboard, and the rest is addressed with radiators. Water will run through the tubing and piping for these levels. Most of the Warmboard will be installed under hardwood floors (standard 3/4” oak) so the water temperature will need to be kept quite low for these areas. I am also looking to put something in the 140 degree neighborhood into the radiators to achieve optimum efficiency.
The garage is a tuck-under (under the first floor), and we are installing hydronic tubing (again ½” PEX) in the slab for the garage as well as the adjacent storage room and mudroom. The total heat load for this “lower level” is approximately 23,000 Btus. Water will run through the tubing for this level.
We are also installing hydronic tubing in the driveway. A glycol solution will run through the tubing here. We do not plan on using the snowmelt system much (we can certainly benefit from the manual labor snow shoveling provides), but given that the driveway slopes into the house, we thought it best to get some help via heat in the event of icy conditions so we do not take out the garage door. The heating load for the snowmelt system is approximately 127,000 Btus.
After the addition, we will have two full baths, one ¾ bath and one ½ bath. The tub in one of the full baths is a “whirlpool” variety that has an approximately 90 gallon capacity. (The tub for the other bath is a relatively shallow “regular” sized tub). There will be two adults and three young children (children all girls) who will be living in the house.
b Queries.
Here are my questions:
1) I would like to come up with the most energy-efficient, reliable and yet economical system possible to provide the needed heat. It also is important to remember that I am not looking to obliterate the snow as it falls – I plan on shoveling and only using the snowmelt sparingly. I am considering using an MZ low mass boiler distributed by Monitor Products. What are people’s thoughts on that boiler (and on low mass boilers in general)? The concept seems to make a lot of sense to me (sports car vs. truck analogy, etc.).
2) I have also been considering a Polaris hot water heater in lieu of (or perhaps in combination with) the MZ. What are the thoughts on this? (The Polaris unit has a 50 gallon tank and approximately 100,000 Btus.
3) Would it be workable to rely on the MZ (say the 94,000 Btu unit or the 142,000 Btu unit) to heat the house (1st and 2nd floors and lower level)? Could I also effectively use the MZ unit to handle the snowmelt and the house (on the rare occasions when it would be used) and alternate between the house and the snowmelt using a priority switch? Would the best way to do this be by running the glycol for the snowmelt through an appropriately sized plate and frame heat exchanger. (The HVAC contractor I am working with is concerned that a heat exchanger will not work appropriately).
4) Would it make sense to try to get even more “bang for my buck” by attempting to use the MZ to provide the heat for potable hot water? Would the best way to do this be to utilize an indirect hot water heater? What brands would be best here? My sense is that the Ergomax tends to work best with real hot water (i.e., around 180 degrees) and that it would not be the most efficient for me to heat that high given the amount of mild or warm water I will need).
5) Alternatively, would it be more efficient and/or more prudent to simply go with a separate power-vented or sealed combustion hot water heater for the domestic potable water? As intimated above, is there a way where I could combine the MZ and the Polaris effectively to address the hydronic needs in the house, the snowmelt and the domestic hot water (again, perhaps through the use of heat exchangers and/or indirect tanks)?
Please let me know if additional information would be helpful or if you have recommendations as to other contacts or resources to explore this with.
Replies
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I have a couple of questions for the group in connection with a sizeable addition project in Minnesota (the addition is approximately 2400 square feet).
b Background.
We are installing hydronic heating in the addition. The total heating load for the first and second floor is approximately 62,000 Btus. Most of this is addressed with ½” PEX in Warmboard, and the rest is addressed with radiators. Water will run through the tubing and piping for these levels. Most of the Warmboard will be installed under hardwood floors (standard 3/4” oak) so the water temperature will need to be kept quite low for these areas. I am also looking to put something in the 140 degree neighborhood into the radiators to achieve optimum efficiency.
The garage is a tuck-under (under the first floor), and we are installing hydronic tubing (again ½” PEX) in the slab for the garage as well as the adjacent storage room and mudroom. The total heat load for this “lower level” is approximately 23,000 Btus. Water will run through the tubing for this level.
We are also installing hydronic tubing in the driveway. A glycol solution will run through the tubing here. We do not plan on using the snowmelt system much (we can certainly benefit from the manual labor snow shoveling provides), but given that the driveway slopes into the house, we thought it best to get some help via heat in the event of icy conditions so we do not take out the garage door. The heating load for the snowmelt system is approximately 127,000 Btus.
After the addition, we will have two full baths, one ¾ bath and one ½ bath. The tub in one of the full baths is a “whirlpool” variety that has an approximately 90 gallon capacity. (The tub for the other bath is a relatively shallow “regular” sized tub). There will be two adults and three young children (children all girls) who will be living in the house.
b Queries.
Here are my questions:
1) I would like to come up with the most energy-efficient, reliable and yet economical system possible to provide the needed heat. It also is important to remember that I am not looking to obliterate the snow as it falls - I plan on shoveling and only using the snowmelt sparingly. I am considering using an MZ low mass boiler distributed by Monitor Products. What are people’s thoughts on that boiler (and on low mass boilers in general)? The concept seems to make a lot of sense to me (sports car vs. truck analogy, etc.).
2) I have also been considering a Polaris hot water heater in lieu of (or perhaps in combination with) the MZ. What are the thoughts on this? (The Polaris unit has a 50 gallon tank and approximately 100,000 Btus.
3) Would it be workable to rely on the MZ (say the 94,000 Btu unit or the 142,000 Btu unit) to heat the house (1st and 2nd floors and lower level)? Could I also effectively use the MZ unit to handle the snowmelt and the house (on the rare occasions when it would be used) and alternate between the house and the snowmelt using a priority switch? Would the best way to do this be by running the glycol for the snowmelt through an appropriately sized plate and frame heat exchanger. (The HVAC contractor I am working with is concerned that a heat exchanger will not work appropriately).
4) Would it make sense to try to get even more “bang for my buck” by attempting to use the MZ to provide the heat for potable hot water? Would the best way to do this be to utilize an indirect hot water heater? What brands would be best here? My sense is that the Ergomax tends to work best with real hot water (i.e., around 180 degrees) and that it would not be the most efficient for me to heat that high given the amount of mild or warm water I will need).
5) Alternatively, would it be more efficient and/or more prudent to simply go with a separate power-vented or sealed combustion hot water heater for the domestic potable water? As intimated above, is there a way where I could combine the MZ and the Polaris effectively to address the hydronic needs in the house, the snowmelt and the domestic hot water (again, perhaps through the use of heat exchangers and/or indirect tanks)?
Please let me know if additional information would be helpful or if you have recommendations as to other contacts or resources to explore this with.