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Thread: Traditional Ducted Heat Pump in Dedicated Workshop

  1. #1
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    Traditional Ducted Heat Pump in Dedicated Workshop

    I last posted here about 3 years ago for advice on a cyclone dust collector. Based on the advice I received here, I had purchased a 5 HP Super Dust Gorilla from Oneida at that time, and due to an unexpected turn in life I never got to use it. I had to put my passion of woodworking on hold. Literally, the cyclone is still new in the box, unused. I feel blessed and fortunate that I can finally put it to use. The nature of my post today, however is about my workshop's heating and cooling system.

    3 years ago, just before I purchased my cyclone, I installed a traditional, ducted heat pump system to heat and cool the workshop ... it also has never been used, and has sat in my workshop waiting to be turned on and put to use for the past 3 years! My workshop is a standalone structure, not connected to my house, so contaminating my house with fine saw dust particles via the ducting system for the heat pump will be a non-issue. The air handler is in a small closet that will have the cold air return within 3 feet of my ShopBot. So, my big concern with this heat pump, after having researched Bill Pentz's website recently, is how the fine saw dust particles that escape my cyclone (and are free floating around in my workshop) will affect my heat pump?

    To maximize fine dust collection, I'm running 6 inch duct to all my tools, and will modify ports on most of my tools to accept a 6 inch connection, but there will be some tools whose ports I cannot modify, and in these instances 4 inch and 2.5 inch duct/flex hose will be the best I can do. My cyclone will be in a closet, with a HEPA filter that is rated at MERV 16, and in this closet there will also be a bathroom style exhaust fan that I'll turn on while I'm working so that any fine saw dust particles that escape out of the cyclone's filter will be contained within the confines of the closet and carried to the outside via the exhaust fan.

    The last thing I want to do is destroy my heat pump with fine sawdust particulate. It only has space for a 20 x 20 x 1 filter, and the highest MERV rating I've found on a 1 inch thick filter is MERV 13. Bill Pentz says to use MERV 15. For anyone running a ducted heat pump in your shop, what precautions are you taking to protect your heat pump?
    Last edited by Jason Fields; 02-21-2019 at 10:14 PM.

  2. #2
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    Here's the planned layout of my workshop, with the air handler (not shown) being positioned within the corner between the jointer and the ShopBot CNC machine. Air diffusers will be mounted overhead in a drop-ceiling.
    Attached Images Attached Images
    Last edited by Jason Fields; 02-22-2019 at 12:05 AM.

  3. #3
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    Jun 2006
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    Northern California
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    Jason it is nice to have heating and cooling in your workshop.
    What size system are you installing? This will help in filter selection.
    I also have a ducted heat pump for my shop. A 1" filter won't cut it in your shop. 1st thing it will be too restrictive. 2nd is you will be changing it quite often. If you can fit it in I would recommend a filter in the return air grill. A 2" pleated would be best. This doe not need to be a high merv rated filter since it will be a pre filter. You should find a way to fit in a filter cabinet that will take a 4" filter. This will be the final filter for the small particles. This can be a merv 8 - 13 your choice. I run a 2" pre filter and a 4" final filter in a filter cabinet and have not had any issues with dust clogging up the system. The fan runs constantly collecting dust when I am in the shop. The pre filter gets change every 1-2 months and the final filter every 6 months or so. I have 20x 25 filters in my system which is 2-ton. This allows for low velocity which helps on dust collection.
    I am a retired HVAC tech and have a fair amount of experience with filtration and measuring performance.

  4. #4
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    Mark, thanks for the information and suggestions. It is going to be great to work in a climate controlled shop space. I have a 2.5 ton air handler that is variable speed, and a 1.5 ton outdoor unit .... already installed (my workshop is approximately 700 sq. ft. .... with an identical size space on the 2nd floor if I want to expand in the future ... same heat pump setup for the 2nd floor as is on the bottom floor). I could fit a 4 inch cabinet underneath my air handler and put the 2 inch pre-filters at a right angle to the air handler intake on the outside of the return air box. It would take some work, but I could make it happen.

    Do you have any recommendations on which filter brand to go with for the 4 inch filter? Also, approximately how many hours per week do you spend in your shop?

    Thanks much.
    Last edited by Jason Fields; 02-22-2019 at 8:23 AM.

  5. #5
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    You can easily incorporate more filtration in your air returns independent of the "on-board" filtration that the unit currently supports. Just build a box that's inline to the air return to hold the filtration you want and have a door that lets you change the media easily. Don't assume you're stuck with the OEM filtration specifications. Of course, more filtration can influence air flow, but unless you go really hog-wild, you likely will be OK.
    --

    The most expensive tool is the one you buy "cheaply" and often...

  6. #6
    And let me just add that although it is a messy job and a bit of a pain, the air exchanger certainly can be and should be cleaned periodically. Sure a shop is likely to be dustier than other settings, but it's not like homes or the world are dust free, far from it. All HVAC equipment should be cleaned reasonably often. Clean yours after 3 or 6 months of use and you'll have a good idea of how often you need to clean it to maintain peak efficiency.

  7. #7
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    Jason,

    I use a 5hp cyclone (ClearVue) in a sound-insulated closet with filtered air returned to the shop (two 9B300NANO Wynn Filters, MERV 15). I also have a 1.5 ton Trane heat pump installed. I've been running both of these for about 4 years.

    I installed the heat pump in a room separate from the wood shop area with a filtered air return through the wall (16x24 I think). Diffusers are overhead in a plywood ceiling. I have a filtered air return I monitor the shop air with a particulate counter. The counts are always low and there is not a fine coat of dust on anything.

    I have seen no problems with the heat pump. I replace the heat pump filters periodically and have never seen any sawdust on/in them even when blowing them out with compressed air. I've inspected the inside of the heat pump and there is no visible fine sawdust in the heat exchanger. I'd worry more about dust on the electronic circuit boards but there is no evidence of that either. If concerned, I suspect an electrostatic filter on the air return plenum could give a bit more peace of mind. (I think the MERV 15 Pentz mentioned is to protect the lungs, not equipment) The air return filter for the house heat pump picks up far more than that in the shop.

    With your attention to dust detail you might consider getting a Dylos or other air quality monitor. I use this one, in use here since 2012: https://www.amazon.com/gp/product/B004AWEG0Y

    BTW, I see a problem with your shop layout plan: I can't find the lathe!

    I can say this: heat and air in the shop certainly increases the quality of life! I can use my shop year-round while i read that some don't play much when it's freezing or very hot outside.

    JKJ

    Quote Originally Posted by Jason Fields View Post
    I last posted here about 3 years ago for advice on a cyclone dust collector. Based on the advice I received here, I had purchased a 5 HP Super Dust Gorilla from Oneida at that time, and due to an unexpected turn in life I never got to use it. I had to put my passion of woodworking on hold. Literally, the cyclone is still new in the box, unused. I feel blessed and fortunate that I can finally put it to use. The nature of my post today, however is about my workshop's heating and cooling system.

    3 years ago, just before I purchased my cyclone, I installed a traditional, ducted heat pump system to heat and cool the workshop ... it also has never been used, and has sat in my workshop waiting to be turned on and put to use for the past 3 years! My workshop is a standalone structure, not connected to my house, so contaminating my house with fine saw dust particles via the ducting system for the heat pump will be a non-issue. The air handler is in a small closet that will have the cold air return within 3 feet of my ShopBot. So, my big concern with this heat pump, after having researched Bill Pentz's website recently, is how the fine saw dust particles that escape my cyclone (and are free floating around in my workshop) will affect my heat pump?

    To maximize fine dust collection, I'm running 6 inch duct to all my tools, and will modify ports on most of my tools to accept a 6 inch connection, but there will be some tools whose ports I cannot modify, and in these instances 4 inch and 2.5 inch duct/flex hose will be the best I can do. My cyclone will be in a closet, with a HEPA filter that is rated at MERV 16, and in this closet there will also be a bathroom style exhaust fan that I'll turn on while I'm working so that any fine saw dust particles that escape out of the cyclone's filter will be contained within the confines of the closet and carried to the outside via the exhaust fan.

    The last thing I want to do is destroy my heat pump with fine sawdust particulate. It only has space for a 20 x 20 x 1 filter, and the highest MERV rating I've found on a 1 inch thick filter is MERV 13. Bill Pentz says to use MERV 15. For anyone running a ducted heat pump in your shop, what precautions are you taking to protect your heat pump?

  8. #8
    Join Date
    Dec 2015
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    Virginia
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    Quote Originally Posted by Jim Becker View Post
    You can easily incorporate more filtration in your air returns independent of the "on-board" filtration that the unit currently supports. Just build a box that's inline to the air return to hold the filtration you want and have a door that lets you change the media easily. Don't assume you're stuck with the OEM filtration specifications. Of course, more filtration can influence air flow, but unless you go really hog-wild, you likely will be OK.
    I hadn't thought of that Jim, but you're right .... no good reason to buy one of those cabinets/boxes and pay someone to install it and make major modification to my return air duct in doing so, if I can fabricate my own that can be installed in place as the system sits, without major modifications. You've got my wheels turning on this idea .... I think I can make something that will work, as is, and save some money. Thanks.

  9. #9
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    Dec 2015
    Location
    Virginia
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    Quote Originally Posted by Paul F Franklin View Post
    And let me just add that although it is a messy job and a bit of a pain, the air exchanger certainly can be and should be cleaned periodically. Sure a shop is likely to be dustier than other settings, but it's not like homes or the world are dust free, far from it. All HVAC equipment should be cleaned reasonably often. Clean yours after 3 or 6 months of use and you'll have a good idea of how often you need to clean it to maintain peak efficiency.
    Thanks for the suggestions, Paul!

  10. #10
    Quote Originally Posted by Jason Fields View Post
    3 years ago, just before I purchased my cyclone, I installed a traditional, ducted heat pump system to heat and cool the workshop ... it also has never been used, and has sat in my workshop waiting to be turned on and put to use for the past 3 years! My workshop is a standalone structure, not connected to my house, so contaminating my house with fine saw dust particles via the ducting system for the heat pump will be a non-issue. The air handler is in a small closet that will have the cold air return within 3 feet of my ShopBot. So, my big concern with this heat pump, after having researched Bill Pentz's website recently, is how the fine saw dust particles that escape my cyclone (and are free floating around in my workshop) will affect my heat pump?

    The last thing I want to do is destroy my heat pump with fine sawdust particulate. It only has space for a 20 x 20 x 1 filter, and the highest MERV rating I've found on a 1 inch thick filter is MERV 13. Bill Pentz says to use MERV 15. For anyone running a ducted heat pump in your shop, what precautions are you taking to protect your heat pump?
    My house has been heated/cooled with a geothermal forced air heat pump for 35+ years. My shop is a converted attached garage and uses the same heat system as the house. The only precaution I took in the shop was to build filter boxes on the shop air returns and installed a merv 11 air filter in each air return, in addition to the whole house filter at the heat pump. I do see dust accumulation on the shop filters. I've had zero problems with my heat pump in regards to dust from the shop. I have inspected the return air ducts coming from the shop and see no visible signs of dust accumulation.

    My 22' x 22' shop has a Bag type Dust Collector and a ceiling mounted air filter (which gets used when I do a lot of sanding with my belt sander).
    Last edited by Lee Schierer; 02-22-2019 at 6:36 PM.
    Lee Schierer
    USNA- '71
    Captain USN(Ret)

    My advice, comments and suggestions are free, but it costs money to run the site. If you found something of value here please give a little something back by becoming a contributor! Please Contribute

  11. #11
    Join Date
    Dec 2015
    Location
    Virginia
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    12
    Hey John, thanks for sharing your real world experience and heat pump info. It sets me at ease as I think our heat pump and DC setups are somewhat similar. I'll take your advice and invest in a Dylos air quality monitor.

    I had a MERV 15 filter in mind so that the heat pump could filter out any lingering fine saw dust (fine saw dust of the sorts that are damaging to our lungs) that doesn't get sucked up into the DC, serving the dual purpose of heating/cooling and acting as an air scrubber, while also protecting my heat pump. But, if my DC does a well enough job in collecting the dust at the source, as it sound is the case with your ClearVue, then I'll just through a simple filter on it, change it regularly, and be done with it. Jim's post has really got me thinking that I can come up with filter system that would require virtually no modifications to my current return air duct .... or at least modifications that couldn't easily be reversed if need be.

    I've got a ways to go before I am skilled enough to use a lathe ... .but I may get a wild hair and purchase one and give it a whirl (no pun intended!)

    Quote Originally Posted by John K Jordan View Post
    Jason,

    I use a 5hp cyclone (ClearVue) in a sound-insulated closet with filtered air returned to the shop (two 9B300NANO Wynn Filters, MERV 15). I also have a 1.5 ton Trane heat pump installed. I've been running both of these for about 4 years.

    I installed the heat pump in a room separate from the wood shop area with a filtered air return through the wall (16x24 I think). Diffusers are overhead in a plywood ceiling. I have a filtered air return I monitor the shop air with a particulate counter. The counts are always low and there is not a fine coat of dust on anything.

    I have seen no problems with the heat pump. I replace the heat pump filters periodically and have never seen any sawdust on/in them even when blowing them out with compressed air. I've inspected the inside of the heat pump and there is no visible fine sawdust in the heat exchanger. I'd worry more about dust on the electronic circuit boards but there is no evidence of that either. If concerned, I suspect an electrostatic filter on the air return plenum could give a bit more peace of mind. (I think the MERV 15 Pentz mentioned is to protect the lungs, not equipment) The air return filter for the house heat pump picks up far more than that in the shop.

    With your attention to dust detail you might consider getting a Dylos or other air quality monitor. I use this one, in use here since 2012: https://www.amazon.com/gp/product/B004AWEG0Y

    BTW, I see a problem with your shop layout plan: I can't find the lathe!

    I can say this: heat and air in the shop certainly increases the quality of life! I can use my shop year-round while i read that some don't play much when it's freezing or very hot outside.

    JKJ
    Last edited by Jason Fields; 02-22-2019 at 7:19 PM.

  12. #12
    Join Date
    Dec 2015
    Location
    Virginia
    Posts
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    Thanks for taking the time to share your experiences heating and cooling your shop with your heat pump, Lee. I appreciate it! After hearing yours, John's, and Mark's experiences I am feeling more confident that this isn't as big of an issue as I had thought. I was unable to find this same information elsewhere on the internet .... and had almost decided not to run my heat pump while working on things that would stir up a lot of dust.

    Quote Originally Posted by Lee Schierer View Post
    My house has been heated/cooled with a geothermal forced air heat pump for 35+ years. My shop is a converted attached garage and uses the same heat system as the house. The only precaution I took in the shop was to build filter boxes on the shop air returns and installed a merv 11 air filter in each air return, in addition to the whole house filter at the heat pump. I do see dust accumulation on the shop filters. I've had zero problems with my heat pump in regards to dust from the shop. I have inspected the return air ducts coming from the shop and see no visible signs of dust accumulation.

    My 22' x 22' shop has a Bag type Dust Collector and a ceiling mounted air filter (which gets used when I do a lot of sanding with my belt sander).

  13. #13
    To reduce the air resistance, when you build your filter boxes make them several times larger that the vent opening and make them with a standard size filter. My filters are 12 x 12 x 1 and I get them from Filtersnow.com.
    Lee Schierer
    USNA- '71
    Captain USN(Ret)

    My advice, comments and suggestions are free, but it costs money to run the site. If you found something of value here please give a little something back by becoming a contributor! Please Contribute

  14. #14
    I use 20x20 filters on the air intake to my furnace, a metal frame with grill made for the purpose. Just wish I had built a box a foot or so high to set the furnace on, so the filter would be up higher on the wall, instead of floor level. Would significantly increase life of the filters.

  15. #15
    Join Date
    Jun 2006
    Location
    Northern California
    Posts
    44
    Jason, everyone has been providing good info so far. Regarding filter brand I wouldn't get hung up on a particular brand. It's not that critical for what we are doing. Merv rating above an 11 without adequate filter area may cause airflow issues with your system. Do you know if the air handler has an ECM motor or not? This can be an issue with a PSC motor.
    The reason for running prefilters is you will save having to replace the expensive main filter frequently.
    I spend on average 20 - 30 hours a week in the shop.

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