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  1. #1

    Cool Options Needed to Replace Ancient Apartment Boilers

    I have two 8 unit buildings in Michigan. They are each heated by a large central boiler circa 1950. None of the units have A/C or individual thermostats. This results in HUGE operational costs and very low occupant satisfaction, as they can't control the temperature at all. The apartments range from 650 sf to 800 sf, and are on crawl spaces with a relatively shallow pitch roof above. The apartments are in the downtown of a fairly affluent area. I need to do something about the heating/cooling situation in order to bring the rents in line with the market.

    I've spent a lot of time reading about the pros and cons of different heating systems. I'd like to investigate putting a series of high velocity heat and AC units in the attic space (1 per apartment). I'm considering this because the ductwork for a LV system is not feasible given the structure I'm dealing with (I think). Both buildings are single story, and the gas and electricity are already individually metered and available at each apartment.

    Okay, so now you have some background, here are the questions: Are HV systems generally suitable for an attic space for both heating and cooling in my area? All of the houses I've ever owned/seen have the HVAC in the unit or in the basement. Has anyone ever heard of such a retrofit on an apartment building? Are the issues with drainage etc. that I've read about with HV systems avoidable via a knowledgeable installer or am I looking for a problem? What type of venting would be required for such an attic installation (assuming natural gas for heat)?

    Thanks for any feedback you can provide.

  2. #2
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    34,057
    HV air handlers don't have provision for gas heat. They can have a water coil for hot water off a boiler. Or electric heat with straight cool or heat pump though I hate seeing a heat pump on HV air handlers due to the low airflow. They are great to be in an attic.

  3. #3
    Quote Originally Posted by BaldLoonie View Post
    HV air handlers don't have provision for gas heat. They can have a water coil for hot water off a boiler. Or electric heat with straight cool or heat pump though I hate seeing a heat pump on HV air handlers due to the low airflow. They are great to be in an attic.
    Would a heat pump/electric heat provide sufficient heating in order to keep the units comfortable? Most of the heat here in SE Michigan is natural gas based. How would the operating costs for an electric unit compare to a LV natural gas furnace (I know there are not enough details to really answer that but guesstimate is fine by me.) Could I install a gas fired boiler right next to the HV air handler? Sorry if that's a stupid question.

  4. #4
    Join Date
    Jul 2007
    Location
    The Hot South
    Posts
    1,310
    You could also put in some ductless mini splits or PTAC's

  5. #5
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    6,743
    Quote Originally Posted by Mechblue View Post
    Would a heat pump/electric heat provide sufficient heating in order to keep the units comfortable? Most of the heat here in SE Michigan is natural gas based. How would the operating costs for an electric unit compare to a LV natural gas furnace (I know there are not enough details to really answer that but guesstimate is fine by me.) Could I install a gas fired boiler right next to the HV air handler? Sorry if that's a stupid question.
    I'm sure there is a way to get conventional (LV) duct in, how high is the crawlspace? The operating costs of electric heat would be really high in Michigan, enough to not keep tenants very long. Have some contractors out to take a look and give you some different options.

  6. #6
    This is the Ask Our Pro's forum. In order to post a response here, you must have verified qualifications and have been approved by the AOP Committee. You may ask a question by starting a new thread.

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    Last edited by jpsmith1cm; 05-25-2013 at 09:26 AM. Reason: Non AOP Pro Member

  7. #7
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,551
    HVACCory617

    This is the Ask Our Pro's forum. In order to post a response here, you must have verified qualifications and have been approved by the AOP Committee. You may ask a question by starting a new thread.

    You can find the rules for posting and qualifications here.

    Additional infractions may result in loss of posting privileges.

  8. #8
    Join Date
    Oct 2009
    Location
    Raleigh, NC
    Posts
    794
    I agree with R123. Those small apartments sound like a great application for mini-splits. You might even be able to put a ducted mini-split in so that the bedroom can have a supply.

  9. #9
    Join Date
    Sep 2002
    Posts
    12,248

    I would do it this way -

    What I would push for would be a HV A/C system for each unit with a hydronic heating coil in the return duct. I like to lay the water coils in right above the large ceiling-mount air-return filter-grille.

    And install a tankless water heater for each unit's domestic hot water.

    And use a small bronze pump and a stainless steel plate frame HX to make the heating water.

    PHM
    ------




    Quote Originally Posted by Mechblue View Post
    I have two 8 unit buildings in Michigan. They are each heated by a large central boiler circa 1950. None of the units have A/C or individual thermostats. This results in HUGE operational costs and very low occupant satisfaction, as they can't control the temperature at all. The apartments range from 650 sf to 800 sf, and are on crawl spaces with a relatively shallow pitch roof above. The apartments are in the downtown of a fairly affluent area. I need to do something about the heating/cooling situation in order to bring the rents in line with the market.

    I've spent a lot of time reading about the pros and cons of different heating systems. I'd like to investigate putting a series of high velocity heat and AC units in the attic space (1 per apartment). I'm considering this because the ductwork for a LV system is not feasible given the structure I'm dealing with (I think). Both buildings are single story, and the gas and electricity are already individually metered and available at each apartment.

    Okay, so now you have some background, here are the questions: Are HV systems generally suitable for an attic space for both heating and cooling in my area? All of the houses I've ever owned/seen have the HVAC in the unit or in the basement. Has anyone ever heard of such a retrofit on an apartment building? Are the issues with drainage etc. that I've read about with HV systems avoidable via a knowledgeable installer or am I looking for a problem? What type of venting would be required for such an attic installation (assuming natural gas for heat)?

    Thanks for any feedback you can provide.
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  10. #10
    Join Date
    Sep 2002
    Posts
    12,248

    I would do it this way -

    What I would push for would be a HV A/C system for each unit with a hydronic heating coil in the return duct. I like to lay the water coils in right above the large ceiling-mount air-return filter-grille.

    And install a tankless water heater for each unit's domestic hot water.

    And use a small bronze pump and a stainless steel plate frame HX to make the heating water.

    PHM
    ------




    Quote Originally Posted by Mechblue View Post
    I have two 8 unit buildings in Michigan. They are each heated by a large central boiler circa 1950. None of the units have A/C or individual thermostats. This results in HUGE operational costs and very low occupant satisfaction, as they can't control the temperature at all. The apartments range from 650 sf to 800 sf, and are on crawl spaces with a relatively shallow pitch roof above. The apartments are in the downtown of a fairly affluent area. I need to do something about the heating/cooling situation in order to bring the rents in line with the market.

    I've spent a lot of time reading about the pros and cons of different heating systems. I'd like to investigate putting a series of high velocity heat and AC units in the attic space (1 per apartment). I'm considering this because the ductwork for a LV system is not feasible given the structure I'm dealing with (I think). Both buildings are single story, and the gas and electricity are already individually metered and available at each apartment.

    Okay, so now you have some background, here are the questions: Are HV systems generally suitable for an attic space for both heating and cooling in my area? All of the houses I've ever owned/seen have the HVAC in the unit or in the basement. Has anyone ever heard of such a retrofit on an apartment building? Are the issues with drainage etc. that I've read about with HV systems avoidable via a knowledgeable installer or am I looking for a problem? What type of venting would be required for such an attic installation (assuming natural gas for heat)?

    Thanks for any feedback you can provide.
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  11. #11
    Join Date
    Apr 2003
    Location
    Maple Grove, MN
    Posts
    1,271
    Are you trying to push the utility costs onto your tenants, or are you OK with continuing to pay the heating bill?

    You didn't mention what type of boiler system you have, but there are usually cost effective ways to retrofit thermostat controls on the heating units. If you have radiators, they make valves that you can put on them that have a knob that can be set to maintain temperature in the space. They don't need any electricity to make them work. That might be an option worth checking into.

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