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  1. #53
    Join Date
    Oct 2011
    Location
    NJ
    Posts
    149
    Quote Originally Posted by Bear_in_HOU View Post
    Let me perhaps get more clear about the various options under consideration:

    1) Single stage AC + (small) Gas furnace - standard Houston practice, we have this in our current home. Probably two units (one up and one down). If I don't ask for better, this is likely what every contractor my builder polls will spec.
    You can do better. Probably lowest first cost option though.


    Quote Originally Posted by Bear_in_HOU View Post
    2) Single-stage Heat Pump - as above, but without the gas furnace. Electricity runs $0.11/kWhr (more or less) and gas is $0.80/Ccf (more or less). Higher acquisition cost vs. the AC unit, but indeterminate vs. the package.
    In tight, well insulated construction this is worth considering. Have you considered Photovoltaic Solar panels to offset utility costs. This option is not as costly in new construction where the roof is going to be new, the electric system is being installed new, structure for the panels can be designed into the home while it is being built, energy studies required to obtain incentives will probably already be needed for the home design anyway or not required due to the expected levels of insulation etc, and incentives may still be available to make the cost reasonable. Solar makes heat pumps a no-brainer, if it is a viable option for your area (I don't know what the feel is for PV solar down there. I have a ground mounted grid tied 8.8 kW system at my house in NJ and I spent less than $200 last year for my grid tied electric with a 3 ton heatpump, heatpump water heater, an outdoor hot tub, electric cooking and clothes dryer and the usual other electric stuff. We used to average $150 per month plus $2000 per year for oil heat.)

    Quote Originally Posted by Bear_in_HOU View Post
    3) High-efficiency, two-stage iterations of both of the above. Somewhat likely to get "upsold" into a higher tonnage unit(s) to handle peak loads, while the lower speed stage may or may not still be overkill for our average needs. Ductwork and other items also having to be sized to the peak airflow means more added expense.
    The upshot of oversizing is that a heatpump may be able to handle heat load without backup in some models, especially in milder climates for heating.

    Quote Originally Posted by Bear_in_HOU View Post
    4) VRF Heat Pump (Japanese) - Mitsubishi can operate more than one air handler internally (great!), but there are few contractors locally who work with these units (not great), and the ones that seem to work in a ducted application (we need high performance filtration) seem to only have mid-market efficiency ratings. I've read a studies done by FSRC, among others, on these types of units to see what the practical efficiency is. This is still an open question.
    I've used these type units on several projects. The question is open because there is difficulty modeling their capabilities. Commercial load programs couldn't model how they take advantage of part load through compressor load matching also, the ratings system did not extend low enough to show their advantage as a heat pump in colder climates through the ability when optimized for heating to do heatpump operation down to 100% rated capacity at 0 degrees in some models without backup heat. The drawbacks are that by code you have to make provision for the smallest room with an interior unit to be able to handle a dumping of the entire refrigerant charge into the room should a catastrophic failure occur, the units do not handle outside air well without a separate dedicated system, and finding an installer with experience who can do all the refrigerant piping work required. They also need to have provision for condensate removal on a local level (at each indoor unit) and the units are in the room, hanging on a wall, up in a ceiling or standing by a wall. The good news is they are very quiet and if installed right are very efficient.

    I like the dedicated whole house dehumidifier option for treating incoming OA. If it also connects to RA then it will help reduce the latent load on the AC.

    Another option mentioned above in some of the other posts that I have used is the mini chiller system. On the surface these do not appear as efficient as say the VRF minisplits (they look identical by the way), but they can allow for greater diversity for greater possible equipment size reduction. Only water and maybe some glycol (not a very high concentration in your area, I imagine) run through the building so the refrigerant charge is all outdoors so that code restriction of accounting for refrigerant dumping goes away. Installation can be done more easily because it is water piping and not refrigerant, many more contractors can do that kind of installation as certification is less stringent. Well suited to new construction. Same other problems as VRF with condensate disposal. Worth looking into though.

  2. #54
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,467
    Quote Originally Posted by classical View Post
    For the type of home Bear is building a SDHV system with manual N load calc utilizing a Unichiller with Hydronic heat and cool staged and zoned he will have near perfect comfort with low utility bills including DHW. Considering the high west load a staged zoned system would be perfect.

    I really do not know of another company that does this in Houston but I am sure UNICO could make a recommendation.

    I would love to do a home like this but I am enjoying being retired from the BIZ and there is not enough money to drag me back.

    And yes supplemental dehumidification would be very beneficial in a home of this type. Bear stay away from an ERV in Houston they are not worth the expense especially since it is not that much more for a qualty unit from UltraAire.
    Good to here from you again. Thanks for the support. There are many exciting mechanical ways to provide ideal temp/%RH throughout all the different weather conditions.
    For long term affordability and simplicity, I like the simple med SEER a/cs and a whole dehu. Not much fun though.
    Keep us posted on your retirement and any new concepts you feel might fix the problems we are faced with. I am older that you but continue to keep my finger in this bussiness.
    Regards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  3. #55
    Quote Originally Posted by Mr Bill View Post
    Al, his biggest issue in Houston, is going to be someone that is willing to take on the responsibility, of guaranteeing the outcome of his expectations. Probably have better luck in the off season, finding someone that is willing to spend some time on his project. Problem is with any a/c sale, it's impossible to know exactly what the homeowner expects, especially on a new build, because you have nothing like an existing ac system to compare it to.
    somehow I feel judged for even trying to get educated about HVAC -- something mentioned in a lot of other threads -- prior to the first shovel being put in the proverbial soil.

    Is he going to be the GC on the job?
    Not a chance.
    If not he will have to tell the builder he will handle the ac part, most GC's don't like that, and are not very corporative with the ac contractor on the job, been there done that before.
    I have never spent money on a car without a test drive. I'm not sure why I would take the lowest bid on HVAC (with a $10k+ price tag), and not know a little bit about the purchase ahead of time.

    Al, even if your retired, this would be a good pocket change job you could supervise, unless your just spending all your time and money traveling the world. I thought about at least simi-retiring, but I don't travel much, I am pretty much a home body, retiring would turn me into a recluse.


    Sent from my iPhone using Tapatalk
    Not that it should have been relevant for this discussion, but I chose my builder because he was interested in having a client who cared about the craftsmanship of building a home as much as he cared himself. He knows that I am going to be beyond 'Type A' on things like flashing details and air sealing. The upside for him, beyond that he makes a nice profit margin, is that it gives him a reference to send other clients when he wants to talk about things like insulation values and air sealing -- one that is even more passionate, perhaps, than he is.

  4. #56
    Quote Originally Posted by motoguy128 View Post
    Tell you what... just blue print my home, move some walls around so you can have a more ecclectic, inefficient, hodgepodged modern layout, spray foam the wall cavities use a cool roof, drop the window area to a more reasonable amount to keep your constrution costs in control, and I'll guarantee you can cool the whole place with 2 tons... and it won;t matter when thermsotat or equipment you use, since it will be cool, dry and even temps all the time. It was designed almost 90 years years ago by someone that I think was a lot smarter and mroe expereinced than those designing houses now. It was built at a time when AC didn;t exist in residential homes, so it built in features to cool a home naturally. Why reinvent the wheel.
    Generous offer. I think that there may be some kids on your lawn...

  5. #57
    Quote Originally Posted by classical View Post
    Bear call and talk to Dr. Heat Professor Cool in League City or Contact Jason from this site. Now that I am retired they will be your best bet for a proper design and install. I do not know of anyone in Houston that does quality work that does Unico.
    Will do. I think Dr. Heat Professor Cool was on one of my lists of potential vendors.

    I seriously doubt you will need 2-tons total cooling for this house.
    For most of the day, I sure hope so.

    Best option but expensive UNICO with Unichiller w/dehumidifier, next best Infinity/Greenspeed or comparable Lennox product w/dehumidifier. The only reason I recommend a 2-stage system is because of your peak load with west wall fenestration.

    Zoning is also recommended and the Lennox and Carrier equipment have the best zone products.
    Local UNICO rep left me voice mail while I was at lunch. I really hate that the Lennox iComfort t-stat requires a subscription. It's borderline offensive, actually. I haven't found the similar information on Carrier.

  6. #58
    Quote Originally Posted by vangoghsear View Post
    Have you considered Photovoltaic Solar panels to offset utility costs.
    In the broader ERCOT market, we only have Federal subsidies. The upside is that we have a competitive (but small) residential solar industry (install costs are running ~$5/watt before tax credits). We'll get bids a bit later, but the house is being designed to dedicate the southern exposure to PV. We should be able to fit up to a 6kW system. Since I've lived through two hurricanes here with 2 week+ power outages, solar PV and a back-up generator are on the list of nice-to-haves.

    The upshot of oversizing is that a heatpump may be able to handle heat load without backup in some models, especially in milder climates for heating.
    I have enough toys (e.g., receivers, TVs, computers, etc.) with standby plug loads that we may not need active heating for much of our "winter".

    I've used these type units on several projects. The question is open because there is difficulty modeling their capabilities. Commercial load programs couldn't model how they take advantage of part load through compressor load matching also, the ratings system did not extend low enough to show their advantage as a heat pump in colder climates through the ability when optimized for heating to do heatpump operation down to 100% rated capacity at 0 degrees in some models without backup heat. The drawbacks are that by code you have to make provision for the smallest room with an interior unit to be able to handle a dumping of the entire refrigerant charge into the room should a catastrophic failure occur, the units do not handle outside air well without a separate dedicated system, and finding an installer with experience who can do all the refrigerant piping work required. They also need to have provision for condensate removal on a local level (at each indoor unit) and the units are in the room, hanging on a wall, up in a ceiling or standing by a wall. The good news is they are very quiet and if installed right are very efficient.

    I like the dedicated whole house dehumidifier option for treating incoming OA. If it also connects to RA then it will help reduce the latent load on the AC.

    Another option mentioned above in some of the other posts that I have used is the mini chiller system. On the surface these do not appear as efficient as say the VRF minisplits (they look identical by the way), but they can allow for greater diversity for greater possible equipment size reduction. Only water and maybe some glycol (not a very high concentration in your area, I imagine) run through the building so the refrigerant charge is all outdoors so that code restriction of accounting for refrigerant dumping goes away. Installation can be done more easily because it is water piping and not refrigerant, many more contractors can do that kind of installation as certification is less stringent. Well suited to new construction. Same other problems as VRF with condensate disposal. Worth looking into though.
    I'm not wild about having mini-splits -- too many filters to change, among other things. If we go with a VRF system, it would be with a traditional duct system and variable-speed AHU.

  7. #59
    Join Date
    Oct 2011
    Location
    NJ
    Posts
    149
    Quote Originally Posted by Bear_in_HOU View Post
    In the broader ERCOT market, we only have Federal subsidies. The upside is that we have a competitive (but small) residential solar industry (install costs are running ~$5/watt before tax credits). We'll get bids a bit later, but the house is being designed to dedicate the southern exposure to PV. We should be able to fit up to a 6kW system. Since I've lived through two hurricanes here with 2 week+ power outages, solar PV and a back-up generator are on the list of nice-to-haves.


    I have enough toys (e.g., receivers, TVs, computers, etc.) with standby plug loads that we may not need active heating for much of our "winter".


    I'm not wild about having mini-splits -- too many filters to change, among other things. If we go with a VRF system, it would be with a traditional duct system and variable-speed AHU.
    Glad to hear you are considering the solar. Lots of advantages in new construction to keep the cost more reasonable. 30k for 6 kW isn't too bad.

    I think you may lose too much efficiency using the VRF without the mini splits. Some zoning may help, perhaps adding a peak load FC unit to help handle that westward facing room, but you may end up just paying more for what you could get from a med eff split system.

    Some brands of VRF, LG for instance have a electronic plasma filtering and decorative wall units, just sayin' in case you weren't aware.

    I like the mini-chiller systems too. You could put in a chiller sized to cover just your average load and add a buffer tank (a good idea with small systems anyway) sized to even out system operation, reduce compressor cycling on low load days, and help cover the peak load in that Westward room. Again though, you may need some zoning to really take advantage of capacity reduction.
    Last edited by vangoghsear; 06-24-2013 at 05:24 PM.

  8. #60
    Join Date
    Dec 2002
    Location
    Houston,Tx.
    Posts
    16,008
    Quote Originally Posted by Mr Bill View Post
    Al, even if your retired, this would be a good pocket change job you could supervise, unless your just spending all your time and money traveling the world. I thought about at least simi-retiring, but I don't travel much, I am pretty much a home body, retiring would turn me into a recluse.
    Quote Originally Posted by Bear_in_HOU View Post
    Not that it should have been relevant for this discussion, but I chose my builder because he was interested in having a client who cared about the craftsmanship of building a home as much as he cared himself. He knows that I am going to be beyond 'Type A' on things like flashing details and air sealing. The upside for him, beyond that he makes a nice profit margin, is that it gives him a reference to send other clients when he wants to talk about things like insulation values and air sealing -- one that is even more passionate, perhaps, than he is.
    Just wanted to come back and let you know, my quote up there was sort of an inside joke. Al is younger than me, so he must have lost interest in the business, or won the lotto. I actually Love this business, and would probably never retire even if I won the lotto. Not only that, I feel a responsibility to be around for the folks that help build this business, my customers. I probably could retire now, but I will wait till the old ticker stops beating to retire.
    __________________________________________________ _______________________
    “Experience is a hard teacher because she gives the test first, the lesson afterwards". - Vernon Law

    "Never let success go to your head, and never let failure go to your heart". - Unknown

  9. #61
    Join Date
    Dec 2002
    Location
    Houston,Tx.
    Posts
    16,008
    Quote Originally Posted by Bear_in_HOU View Post
    somehow I feel judged for even trying to get educated about HVAC -- something mentioned in a lot of other threads -- prior to the first shovel being put in the proverbial soil.
    I haven't seen any post, unless you read more into them than I have, that would seem anyone was being judgmental. Think about it for a moment, there is nothing wrong at all with your endeavor, it's just most folks are more into cosmetics, than the really important things like a/c, etc. and to back that statement up, look how hard it's been to locate someone in Houston, that can help you with your project. Most a/c company's in Houston, would give you the deer in the headlights look, if you had them out to explain your plan. Hey most of us "including me' Love to be involved with an informed homeowner, it makes my job a lot easier when were on the same page.
    __________________________________________________ _______________________
    “Experience is a hard teacher because she gives the test first, the lesson afterwards". - Vernon Law

    "Never let success go to your head, and never let failure go to your heart". - Unknown

  10. #62
    Join Date
    May 2002
    Location
    Houston Texas
    Posts
    6,325
    Quote Originally Posted by Mr Bill View Post
    Just wanted to come back and let you know, my quote up there was sort of an inside joke. Al is younger than me, so he must have lost interest in the business, or won the lotto. I actually Love this business, and would probably never retire even if I won the lotto. Not only that, I feel a responsibility to be around for the folks that help build this business, my customers. I probably could retire now, but I will wait till the old ticker stops beating to retire.
    Yes I just got fed up with fighting the battle over expectingto be paid for what I offered, the low ball, ill informed poor quality contractors and the customers that want it all for nothing just made it no fun anymore.

    I bought a new truck and trailer and travel the country checking out the sites, headed for W/ Virginia in the AM.

  11. #63
    Quote Originally Posted by Mr Bill View Post
    I haven't seen any post, unless you read more into them than I have, that would seem anyone was being judgmental. Think about it for a moment, there is nothing wrong at all with your endeavor, it's just most folks are more into cosmetics, than the really important things like a/c, etc. and to back that statement up, look how hard it's been to locate someone in Houston, that can help you with your project. Most a/c company's in Houston, would give you the deer in the headlights look, if you had them out to explain your plan. Hey most of us "including me' Love to be involved with an informed homeowner, it makes my job a lot easier when were on the same page.
    I may have read more into it, then. Perhaps what I get for trying to read too quickly a couple of pages of responses from people generously supplying a career's worth of knowledge. I do appreciate the help. :-)

    My next meeting with the architect is July 3rd. I should know more about when we break ground by then (design schedule is on the agenda). Key upcoming decisions from an HVAC standpoint: where to put air handlers? Where to put the condenser(s)? Then the builder and the architect get to start fighting over cost vs. vision.

  12. #64
    Quote Originally Posted by vangoghsear View Post
    Glad to hear you are considering the solar. Lots of advantages in new construction to keep the cost more reasonable. 30k for 6 kW isn't too bad.

    I think you may lose too much efficiency using the VRF without the mini splits. Some zoning may help, perhaps adding a peak load FC unit to help handle that westward facing room, but you may end up just paying more for what you could get from a med eff split system.
    This has been a big question mark with the ducted VRFs. There is a minimum efficiency spec, but it is hard to discern how to compare that versus a 'standard' system. It sounds like the price premium is significant with a minimal performance improvement, esp. vs. domestic brands, if any.

    Some brands of VRF, LG for instance have a electronic plasma filtering and decorative wall units, just sayin' in case you weren't aware.
    It's really the filters. That, and I think that mini-splits are mostly for elevators around here.

    I like the mini-chiller systems too. You could put in a chiller sized to cover just your average load and add a buffer tank (a good idea with small systems anyway) sized to even out system operation, reduce compressor cycling on low load days, and help cover the peak load in that Westward room. Again though, you may need some zoning to really take advantage of capacity reduction.
    Any specific recommendations beyond UNICO? I've not even heard of mini-chillers until it came up here. I thought chilled water systems were strictly for the Big Boys.

  13. #65
    Quote Originally Posted by classical View Post
    Yes I just got fed up with fighting the battle over expectingto be paid for what I offered, the low ball, ill informed poor quality contractors and the customers that want it all for nothing just made it no fun anymore.

    I bought a new truck and trailer and travel the country checking out the sites, headed for W/ Virginia in the AM.
    If I go with the guys you suggest, hopefully they won't spit when they mention the project.

    Looks like Carrier doesn't require a monthly subscription for its wireless t-stat. That alone would give it the edge in our household.

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