Where are you? I might guess Houston?????? If so, we got some good Houstonians, if that's what you call yourselves, on here who will be a great source of advice.
I have read a lot about the Trane 16i and 19i, as well as some other systems. We are building a new house in Houston, lots of heat and high humidity. Since we have the opportunity to start from scratch, what is the best recommendation in terms of a/c, heat pump, furnace, and compressor?
Our main concerns: clean air, high efficiency (but no need to waste money just for the newest tech), and reliability.
We have heard about systems that can control venting to specific rooms, clean air, etc. It is all a bit overwhelming, and we need to pick a system in the next few weeks.
All comments are appreciated.
Where are you? I might guess Houston?????? If so, we got some good Houstonians, if that's what you call yourselves, on here who will be a great source of advice.
variable speed ahu's. 2 systems ,,Media filtration,
Seperate HEPA filtration units.
watch out for fresh air intakes that are unfiltered and uncondtioned.
h
the best value is the contractor that will do a heat load calculation and properly calculate the size of your duct work for proper airflow
don't go with lowest bid because they cut corners in order to make a buck
I dont warranty Tinkeritus
What will work best in Houston depends on your lifestyle the design of your house and the type of materials used to build it.
The very most important component will be the ductwork it should also be the most expensive component. If the ductwork is poorly designed and installed no equipment will work well.
Forget the brand game because for the most part brand is irrelevant. Zoning is an excellent choice for a home the size of yours and will provide the greatest comfort and efficiency if properly designed and installed.
A properly installed HVAC system should run about 8% to 11% of the total for the house. In Houston you will find contractors that will install new homes from $1,000.00 per ton to $10,000.00 per ton you get what you pay for. Guaranteed if you go with the GC recommendation you will get a sub par system.
In what part of town are you building that can also make a difference.
Thanks, I am in Houston. I have heard there are systems that can zone even specific rooms. I suppose that must come from automatic dampeners in the ductwork? Is there such a thing, and are they reliable?
For starters, ...
Where did you locate your equipment room(s)?
Attic insulation shall be R-19 minimum spray foam.
Windows shall be tinted, SHGC 0.55 maximum.
Overhangs for any South, East or West facing windows should be ~8 feet
Now you can start an HVAC load analysis and layout.
You can provide the HVAC design and your specs to several mechanical contractors.
Designer Dan __ It's Not Rocket Science, But It is SCIENCE with Some Art. _ _ KEEP IT SIMPLE & SINCERE ___ __ www.mysimplifiedhvac.com ___ __ Define the Building Envelope & Perform a Detailed Load Calc: It's ALL About Windows & Make-up Air Requirements. Know Your Equipment Capabilities
Yes there are such systems my house is 2800 sq.ft. and I have four zones. I install zoned systems all the time and have a very minimal component failure rate. In fact my system is 7-years old and never any problems. In the last ten years I have had three or four bad dampers and one bad control board and that board failed on start up so yes zone controls are very reliable when properly designed and installed.
Going to the extreme of controlling each room is possible but not recommended. Especially in Houston because proper humidity control would be difficult to achieve. In could be done but you would need to install top of the line all the way and add supplemental dehumidification.
Depending on what materials you are using to construct the house best option for a 5000 sq.ft. two stories would be two 4-ton or 5-ton 2-stage units with two possibly three zones each. Currently the Bryant Evolution system with zoning would be your best choice. The Lennox Harmony is an excellent option but is not technically up to the Bryant and Tranes zoning controls from what I have been able to ascertain are less than comparable to either.
What it boils down to is the technology is available to do almost anything you want; you just need to balance technology with your desires and your pocket book.
I will be glad to discuss option with you if you like. My number is in my profile.
Going from 16 SEER to 19 SEER can be wasted $$$. If you had a ton / 700 sqft, and you ran at full speed (stage 2) for 1000 hours, the annual savings would be $124.34 according to the formula below (add hours = Larger annual savings for high SEER). Get a quote for both systems, divide the difference by $124.34. This is the number of years longer it takes to start saving money with a 19 SEER.
Spend your $$$ on a non-leaky duct system, and some zoning.
BTU x Annual Hours Running x $ KWH / SEER / 1000 = Annual Cost $
BTU 84000
Cooling Hours 1000
KWH $ 0.15
SEER 16
W/KWH 1000
Annual Cost $787.50
BTU 84000
Cooling Hours 1000
KWH $ 0.15
SEER 19
W/KWH 1000
Annual Cost $663.16
16 SEER to 19 SEER Annual Energy savings: $124.34
Pay attention to the design details on the house.
#1 - either make the attic part of the conditioned space, or get the A/C equipment and duct work out of the attic.
#2 - site the house such that most of the windows are on the north and south - and SHADE all of the windows as much as possible.
#3 - cut air infiltration. Set a design goal of less than 2ACH50 and then do a blower door test to make sure you got there.
The above three items can cut your A/C bill in half or better.
minimum A/C requirements - knowlegeable installer (this is the hard part and the most important), variable speed blower, media filter.
Operating Hours is ~ 2,200 for Houston
XL19i probably won't actually yield 19 SEER.
In any case, the point of a higher SEER comparision is well made in a simplified manner. Pay-back period can be >> 10 years given that annual savings are likely to be < $250.
Try for your own situation aand comparison :
http://www.hvacopcost.com/
Designer Dan __ It's Not Rocket Science, But It is SCIENCE with Some Art. _ _ KEEP IT SIMPLE & SINCERE ___ __ www.mysimplifiedhvac.com ___ __ Define the Building Envelope & Perform a Detailed Load Calc: It's ALL About Windows & Make-up Air Requirements. Know Your Equipment Capabilities
Not any mention of fresh air ventilation and humidity control? I am attaching a word doc showing the specifics about humid Houston weather. Fresh air and maintaing <50%RH are the most important points of indoor air quality and comfort. Ultra-Aire/Honeywell/Lennox/others are selling whole house ventilating dehumidifiers that provide fresh, clean, dry air to home while maintaining <50%RH during the low or no cooling load conditions. I realize that this is not simple. Keep us posted. Regards TB
Last edited by teddy bear; 11-13-2007 at 03:17 PM. Reason: forgot attachment
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"
We received a quote from one contractor today who believes that even the 16 seer would be overkill. He reccomends a 13 seer, with three units, a 2.5, a 3 and a 4 ton unit (calculated with J Manual).
I asked about the 90% furnace as opposed to the 80, and he did not think it would be worth it.
He also thought we would not have any savings for moving up to the 16 seer, the higher efficiency furnace, or single room zoning.
Lastly, we talked about the Trane "clean effects" vs a media filter. Do any of you have any thoughts about whether the media filter would be adequate, or is the Trane or some other clean air system really worth the money.
Thank you for any replies.
I can't begin to tell you how wrong this person is. A sixteen SEER unit will save considerable money over a 13 SEER and will provide a much more comfortable drier home at a much higher temperature. Zoning can save energy and will definitely increase comfort and control. Many especially those that primarily install in new homes are not that well versed in new or more complicated technologies. Their primary interest is to get in and get out in the least time using the least labor and materials possible. The RNC market has a different mindset than those that are more focused on retro fit work.
Installing 16 SEER equipment may not be the right option since it will be 2-stage but 14 or 15 SEER should definitely be considered. All 13 SEER equipment is builder’s grade and will have minimal warranties few if any safeties. The higher quality 14 or 15 SEER units are without a doubt worth the extra money just for the quality of the product.
As to the Clean Effects or any electronic filter system, they all have benefits over standard media filters. The question is do you need them; most benefit of filtration is for the equipment. It will keep the equipment cleaner which will increase equipment life and efficiency. If your family has serious allergy problems then the more expensive electronic filter could be beneficial but for most people a regular extended media filter is more than sufficient.
I do agree that there is no reason in Houston to spend the money for a 90% furnace over an 80% but it is definitely worth spending extra money on a variable speed furnace.
I am curious what company you have a quote from and have you checked their references. Were they recommended by your builder or are you going the owner builder route.
Thanks for the post. This is a contractor the builder has used in other jobs, but I am on a cost-plus arrangemetn so I have some flexibility.
Why would a 2 stage not be desireable here? We have 3 seperate unites for different parts of the house, but I figured a 2 stage could run longer at low speeds at lower costs and help clean the air as well. We only set our house at 78-79 now even in summer, so I venture to guess we don't use our AC as much as others.
i do want to work on the humidity, and that is an important factor as well.
I think you misunderstood 2-stage is very desirable in Houston. I w as referring to your comment that the contractor said 13 SEER was all you needed. Most units rated 16 SEER or above are two-stage.
A 2-stage unit when installed properly will provide superior humidity control over a single stage unit. They also allow for slight system over sizing with out determent to comfort or efficiency. Slight over sizing is helpful if you are going to entertain.
I have found for most people with homes the size of yours a combination of single and two-stage units is the best combination. Here again you need to evaluate with your contractor your lifestyle and what your expectations are for the systems.
In Houston you are not a SEER market, you are an EER market... Do your homework. The XL19i has some EER's down in the 10's.
Me thinks you can do better.
Sorry, I am not sure what the difference is, and most contractors I have spoken to only refer to seer. They did say that a heat pump was not a good idea for Houston, because the AC will be more efficient and gas heat will be cheaper as well.
I would definitely go with 2 stage outdoor unit and Variable Speed indoor blower.
Whether a heat pump or gas furnace would be better depends on your climate and utility rates, but I would lean toward a heat pump. Of course I have never lived in Houston, so that may be BS.
I can see no reason to go 13 SEER unless you have VERY LOW utility rates.
Good luck.
Remember, Air Conditioning begins with AIR.
I think you should shop for your own hvac contractor.
The builder works with his hvac company often, and is purchasing
what is known as a builder's grade or entry level hvac system.
This is why you are getting a multisystem install.
If you compare the cost of zoned system against the cost of multiple unit installs
you will get a better average of costs. I find they come out pretty close.
Even for the few extra dollars you will spend for the zoned system the comfort will
be well worth it.
I also second the vairiable speed system, and in my hot humid climates we do a lot
of heatpumps. I perfer gas if it is available, and yeah I admit it...the 90+ furnace.
In my area gas prices are higher than electric, but go 200 miles in any direction from here & it changes.
13 SEER is the least efficient hvac system that you can purchase. (see builder's grade)
As you can expect your hvac system to last for 15 to 20 years I would shop as wisely for it as for the other items of importance to you in your new home.
In 2007 the minimum SEER was raised from 10 SEER to 13 SEER. This is why your builder is saying that this is all you need...it is the minimum.
Use your cost plus for upgrades like Radiant barrier roof decking (techshield..solarply)
R-38 attic insulation, windows with Ufactors & Solar Heat Gain Coefficients (shgc)
of less than .35 R-15 insulation in 2x4 walls and use a 1" foil faced sheating board to the exterior of walls. Ait tight drywall approach for walls and Insulation Contact Air Tight
recessed lights (ICAT)
These things can not be as easily upgraded later or at as less of a cost as now, and will
make your home easier to heat & cool as the home will be tighter.
Make sure that your hvac contractor mastic seals your ductwork, and check for quality control on flashing details for windows, doors & roofs.
There is a great book called Builder's Guide to Hot Humid Climates by Joe Lstiburek
it would be a great asset to you in your build.
Best of luck with your build.
The cure of the part should not be attempted without the cure of the whole. ~Plato