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  1. #14
    Join Date
    Sep 2008
    Location
    New York
    Posts
    131
    As long as you build what you put on the plans the manual J can be done based on the plans

  2. #15
    Join Date
    Jan 2009
    Location
    Fairfield county Connecticuit
    Posts
    778
    I service Westchester county NY

  3. #16
    Join Date
    Jul 2008
    Location
    Rochester NY
    Posts
    4,763
    Get the audit now. It may help with design and specifications for your addition, particularly since you are changing ceiling heights. Air sealing before closing ceilings may be a big missed opportunity.
    Which makes more sense to you?
    CONSERVATION - turning your thermostat back and being uncomfortable. Maybe saving 5-10%
    ENERGY EFFICIENCY - leaving your thermostat where everyone is comfortable. Saving 30-70%

    DO THE NUMBERS! Step on a HOMESCALE.
    What is comfort? Well, it AIN'T just TEMPERATURE!

    Energy Obese? An audit is the next step - go to BPI.org, or RESNET, and find an auditor near you.

  4. #17
    Join Date
    Jun 2011
    Posts
    20
    Quote Originally Posted by heatingman View Post
    Pay a third party engineer to design the system for you, then submit that spec to all the different companies.

    This way everyone will be bidding the same thing. Otherwise 20 different contractors will come up with 20 different designs and equipment specs, and you'll only get more confused.

    Heatingman, what type of 3rd party engineer would you recommend I use if I go that route?

    Btw, I did go ahead and apply for the NYS subsidized energy audit program.

  5. #18
    Join Date
    Jun 2011
    Location
    Balmer, Merlin
    Posts
    19
    Quote Originally Posted by heatingman View Post
    Pay a third party engineer to design the system for you, then submit that spec to all the different companies.

    This way everyone will be bidding the same thing. Otherwise 20 different contractors will come up with 20 different designs and equipment specs, and you'll only get more confused.
    Excellent advice...the type that should have come from your architect.

    Quote Originally Posted by tedkidd View Post
    That.

    Or, since you are in NY you might start with an energy audit.

    Here's the application for the free/reduced cost audit. Go to the link in my signature or search "get energy smart" to find someone near you.
    Again, excellent advisement and again...architect issue. What kind of knucklehead designs any type of extensive renovations in this day and age without a baseline? Definitely got the cart in front of the horse. From a design standpoint your aspiring designer can do a lot to save or screw you by attending to these details first rather than as an after thought. Few cases in point.

    I design and build my own buildings, but always with the direct input of the major professional trades that will have to work with what I intend to build. Typically that means Plumber first ('cuz his stuff is the hardest to move around and relocate), HVAC second ('cuz his stuff is tough to move too if I have any interest in optimizing its performance and minimizing my costs, but it's easier to make air move uphill than sewage) and electrician last (partly 'cuz I hate electricians , but mainly 'cuz they can bend their stuff any which way and electrons don't seem to mind).

    New homes are a different animal but the lesson is the same. By designing for the best insulated and most air tight envelope possible, and creating space for my major systems as an integral part of the beginning, I can significantly reduce the time, trouble and aggravation of the people that are being asked to make it drain, make it cool and let there be light. Making life easier on them gets me a lower labor quote 'cuz time is money and we all respect that. Extra tall TJI's and everything possible framed on stacked 24" centers. The duct men and plumbers look at these big wide open spaces and just grin. Chases that are created for function first make my buyers happy 'cuz they can appreciate the idea that sooner or later their dream house is going to need some doctoring, plus the saved plumbing and HVAC labor dollars can be invested in better equipment for the same relative money. Better gear also makes the trades happier 'cuz nobody likes installin' junk.

    Properly staging the performance of each trade's work and making sure that they all get to meet together BEFORE they show up to start...all works to keep everybody in sync, under budget and more focused on the prize. When I sub my HVAC work I always have my plumber there working with them so that everybody gets problems solved quickly and nobody's hackin' at somebody elses work or causing them problems down the road. Helps them make money so I can make money. These are all things that I'd argue your architect should be coordinating. He should also be at least minimally capable of addressing your climate control questions and concerns. These are all things that are part of the craft that they are supposed to have mastered.

  6. #19
    Join Date
    Jun 2011
    Posts
    20
    Quote Originally Posted by worknfool View Post
    Excellent advice...the type that should have come from your architect.



    Again, excellent advisement and again...architect issue. What kind of knucklehead designs any type of extensive renovations in this day and age without a baseline? Definitely got the cart in front of the horse. From a design standpoint your aspiring designer can do a lot to save or screw you by attending to these details first rather than as an after thought. Few cases in point.

    I design and build my own buildings, but always with the direct input of the major professional trades that will have to work with what I intend to build. Typically that means Plumber first ('cuz his stuff is the hardest to move around and relocate), HVAC second ('cuz his stuff is tough to move too if I have any interest in optimizing its performance and minimizing my costs, but it's easier to make air move uphill than sewage) and electrician last (partly 'cuz I hate electricians , but mainly 'cuz they can bend their stuff any which way and electrons don't seem to mind).

    New homes are a different animal but the lesson is the same. By designing for the best insulated and most air tight envelope possible, and creating space for my major systems as an integral part of the beginning, I can significantly reduce the time, trouble and aggravation of the people that are being asked to make it drain, make it cool and let there be light. Making life easier on them gets me a lower labor quote 'cuz time is money and we all respect that. Extra tall TJI's and everything possible framed on stacked 24" centers. The duct men and plumbers look at these big wide open spaces and just grin. Chases that are created for function first make my buyers happy 'cuz they can appreciate the idea that sooner or later their dream house is going to need some doctoring, plus the saved plumbing and HVAC labor dollars can be invested in better equipment for the same relative money. Better gear also makes the trades happier 'cuz nobody likes installin' junk.

    Properly staging the performance of each trade's work and making sure that they all get to meet together BEFORE they show up to start...all works to keep everybody in sync, under budget and more focused on the prize. When I sub my HVAC work I always have my plumber there working with them so that everybody gets problems solved quickly and nobody's hackin' at somebody elses work or causing them problems down the road. Helps them make money so I can make money. These are all things that I'd argue your architect should be coordinating. He should also be at least minimally capable of addressing your climate control questions and concerns. These are all things that are part of the craft that they are supposed to have mastered.
    What you say would make perfect sense if I had actually asked my architect the question. The truth is, as a consumer if I were interested in a typical a/c system I probably would have just called a few friends that have central a/c, gotten references and gone with the "best" proposal. In that case I'd definitely turn the whole shabang over to the architect to work out with the general contractor.

    Yeah, I'm doing more due diligence on my own than might be necessary before running it by the architect. But since I've never even seen a split-unit a/c system myself, I want to be sure that whoever designs it has seen a LOT more than I have. I'd like to think that a decent architect and GC would recognize that there's specialized expertise involved in getting the installation right, but I'd rather not count on that.

  7. #20
    Join Date
    Jun 2011
    Location
    Balmer, Merlin
    Posts
    19
    Never hurts to learn, only costs when ya don't.

  8. #21
    Join Date
    Jun 2011
    Posts
    20

    Energy efficiency of VRF/VRV for heat

    We've been moving along with our research. Yesterday I had an HVAC contractor who has installed a lot of split systems come out to the house.

    It was pretty funny: our architect was appalled by the look of the ductless units and ceiling cassettes, my husband was wringing his hands over the cost, and I'm sitting there -- ever the gearhead that I am -- dazzled by the performance of the VRV/VRF systems.

    Our house currently has hot-water heat with big, old radiators, but to eke out more space we've been thinking about changing over to in-floor radiant heat downstairs and replacing the upstairs radiators with lower profile units. But instead, I'm wondering if we should be considering using the a VRV/VRF system as a heat pump.

    Can anyone speak to the energy efficiency of VRF/VRV systems for heat compared with hot water radiator systems?

  9. #22
    Join Date
    Sep 2006
    Posts
    1,253
    Quote Originally Posted by overhear View Post
    We've been moving along with our research. Yesterday I had an HVAC contractor who has installed a lot of split systems come out to the house.

    It was pretty funny: our architect was appalled by the look of the ductless units and ceiling cassettes, my husband was wringing his hands over the cost, and I'm sitting there -- ever the gearhead that I am -- dazzled by the performance of the VRV/VRF systems.

    Our house currently has hot-water heat with big, old radiators, but to eke out more space we've been thinking about changing over to in-floor radiant heat downstairs and replacing the upstairs radiators with lower profile units. But instead, I'm wondering if we should be considering using the a VRV/VRF system as a heat pump.

    Can anyone speak to the energy efficiency of VRF/VRV systems for heat compared with hot water radiator systems?

    Without knowing the true delivered heat cost of each system it will be hard to compare. Once you have an idea as to what the true operating efficiency numbers are, plus the delivered cost of energy, you can input some basic data at: http://www.warmair.com/html/fuel_cost_comparisons.htm

    Heat pumps decline in heat output the lower the outdoor temps drop and operating efficiency drops too. But, unlike any other method of heat a heat pump gives you more than it is consuming until its breakeven point. This is measured by its COP (Co-efficient of Performance) in which the amount of energy it is consuming is compared to the heat (energy) it is putting out. So the COP drops and once it hits 1 there is no benefit in using the heat pump as a heating source. Most VRV/VRF manufacturers provided extensive data on the heat output and the electric consumption of their systems at numerous different temps.

    Based on your location it would likely make sense to use the heat pump as your primary heat source and the hot water as a supplemental heat source once the heat pump can no longer carry the load on its own.

    With my home the heat pump can provide the required heat to about 14*F but then electric heating coils located in the ducts just down stream form the air handler cycles as needed to maintain the room temp. Heat pump continues to run and produce heat and the electric coils supplement the heat pump as needed.

    The VRV/VRF systems produce more heat at lower temps than conventional heat pumps. I am pleased that my system can produce virtually all the heat my home needs. Our winter design temps are 9*F. The number of hours we spend below 14*F where I need supplemental heat is minimal.

    Also, as a consideration, while not a VRV/VRF system you may want to consider this system form Mitsubishi. It produces 100% of its rated heat output down to 5*F and at -4*F it is rated at 90% of its output. http://www.mehvac.com/UploadedFiles/...0Submittal.pdf

  10. #23
    Join Date
    Jun 2011
    Posts
    20
    Thank you mchild. That's very helpful.

  11. #24
    Join Date
    Jun 2011
    Posts
    20
    Quote Originally Posted by mchild View Post
    ... Also, as a consideration, while not a VRV/VRF system you may want to consider this system form Mitsubishi. It produces 100% of its rated heat output down to 5*F and at -4*F it is rated at 90% of its output. http://www.mehvac.com/UploadedFiles/...0Submittal.pdf
    mchild, Can you clarify which Mitsubishi system that is?

  12. #25
    Join Date
    Sep 2006
    Posts
    1,253
    Quote Originally Posted by overhear View Post
    mchild, Can you clarify which Mitsubishi system that is?
    It is in their H2i Hyper-Heat line up. There are two ducted systems 2.5 and 3 tons and several ductless too. You can look at them here: http://catalog.mitsubishipro.com/cat...ies-heat-pumps

    It is my understanding that they are able to produce the higher heat output at lower temps by using an oversized compressor and then limiting it on the cooling side to 3 tons (by keeping RPMs down) but when outdoor temps drop it will allow the compressor to run at a higher RPM to get the maximum output from it.

    If you want to review the Mitsu products go to mehvac.com and select the Pro site from there. The homeowner side of the site is lame.

  13. #26
    Join Date
    Jun 2011
    Posts
    20
    Quote Originally Posted by mchild View Post
    It is in their H2i Hyper-Heat line up. There are two ducted systems 2.5 and 3 tons and several ductless too. You can look at them here: http://catalog.mitsubishipro.com/cat...ies-heat-pumps

    It is my understanding that they are able to produce the higher heat output at lower temps by using an oversized compressor and then limiting it on the cooling side to 3 tons (by keeping RPMs down) but when outdoor temps drop it will allow the compressor to run at a higher RPM to get the maximum output from it.

    If you want to review the Mitsu products go to mehvac.com and select the Pro site from there. The homeowner side of the site is lame.
    Thanks mchild, I'll take a look. I have the energy audit scheduled for next week. I'm hoping that will give us a better sense of what kind of tonnage we need and also serve as a reality check when bids come in.

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