My mechanical guy is wanting to go up from 5 tons to 6 tons for 4600 heated/cooled sq feet in Memphis TN. I on the other hand want to go down to 4 tons. Its going to be a very tight house. He states that I need enough push to make my long runs. My longest run is 70 feet or so. Is this a valid point? Is there a free or cheaper and easy to use program to calculate HVAC loads. Or possibly a service that i could pay for that could do this. I think people here are stuck with bigger is better and lets face it they get a bigger cut. Also they are using climatemaster tranquility pump and just wanted to get your opinion on the efficiency and reliability of this pump. A friend on mine says trane is better. Thanks ya'll.

I just sent you a private message.

Climatemasters are excellent units. Keep in mind that the 6 ton is very inefficient (relatively speaking), about 10% less than 5 ton, and 5 ton is quite less efficient than the 4 ton.

Climatemasters are excellent units. Keep in mind that the 6 ton is very inefficient (relatively speaking), about 10% less than 5 ton, and 5 ton is quite less efficient than the 4 ton. What is the heat and cooling load?

Good brand advice. That's what i need help with. Im shooting for 4 tons but everyone else wants 5-6 tons. Whats the best recommended program to calculate this or is there a service I can hire to perform this. Thanks ya'll.

"He states that I need enough push to make my long runs. My longest run is 70 feet or so. Is this a valid point? Is there a free or cheaper and easy to use program to calculate HVAC loads. Or possibly a service that i could pay for that could do this."

Upping tonnage strictly for long ductwork runs is unjustified. A high static (capable of higher air pressure) blower option is available on 3 and 4 ton systems. I install WaterFurnace, but no gripes with ClimateMaster...you pick the contractor, let him / her pick the system brand.

We routinely achieve 1200 - 1500 SF per ton for new construction; 1000 SF per ton for production home retrofits. OTOH, I have a 4500 SF beachfront home wrapping up that demanded 7 tons; client insisted upon a half acre of unshaded west glass with aluminum mullions with no thermal breaks. Much depends on specific circumstances of the project.

HVAC Calc (http://www.hvaccalc.com/) is available online with a 60 day license for $50, intended for homeowners rolling their own. I found it closely matched a mainstream package, Elitesoft, that I have used for 4-5 years. If you roll your own you can run calcs on alternative scenarios such as augmented insulation in walls and ceilings, sprayfoam, improved window energy coefficients, reduced air leakage, etc.

There is an outfit out on the net charging big bucks ($1000+) for whole-house-as-1-room-Manual J load calculations... tonnage only...avoid that...high buck, low value - no use for duct or zoning design.

We do remote consulting - since you are building a fairly large house you might be well served to consider ALL its energy centers...HVAC, hot water, laundry, kitchen, lighting, media, pool filter pumping. Whole house energy use can be cut by half or more with reasonable attention to details during construction.

Great...just bought the hvaccalc program and will get started. Hoping for a flashing sign at the end that says 4 tons. Thanks

I agree with others, oversizing the unit will not help with long duct runs. WaterFurnace has a high static option on the 4 ton system so it has the same blower as a 5 ton system. If this is a new construction home have them add zoning so you are not pushing as much air. You can also look into the WaterFurnace 7 Series NVV048 unit which is a variable capacity ground source heat pump that beats the pants off all other two stage ground source heat pumps. It also provides more heat and more cooling than a conventional two stage ground source heat pump while achieving a rated 5.3COP and 41EER at partial load.

Okay so I got the hvac program and calculated my btus. 36,000 gain and 49000 loss. It is actually recommending 3 tons not 4. Why is this so far off from the mechanical people's recommendation? Does this seem like an accurate number to yall. 1/3 came from windows, 1/3 from walls, ceilings and doors, and 1/3 from people and infiltration. And what does the BTUs loss mean. Is that for heating? Do i need a bigger unit for heating? Thanks

The software is saying you need a 3 ton air conditioner and need 4 tons of heating, however you don't want to oversize your AC by putting in a 4 ton heat pump because then you will not get proper dehumidification. The additional 12K BTU's needed can be made up with backup electric heat strips. However, If it was me, I would put in a 4 ton ground source heat pump and here is why, typically a ground source heat pump is rated at 77 degree summer entering water temperature and 32 degree winter entering water temperature. However in Portland we see entering water temperatures into the 80's and occasionaly 90s which means that first stage is only cooling with 36K BTU's based on actual conditions on a WaterFurnace NDV049. During the winter I show a 3 ton unit(which your software recommended) only providing 29K BTU's of heat with 40 degree entering water temperature with a Water Furnace NDV049 or almost 20K BTU's short which I would not want to make up with electric heat strips.

This is why we put in the WaterFurnace 7 series in so many situations, with 14 stages of heating and 12 stages of cooling it will be the best for your situation since you can put in a 4 ton unit and meet the heat load, yet it will only run at 60% of capacity or less and meet your cooling load.

Sounds like a 4 ton to me, 1st stage will be well sized for the cooling load. You can increase the ECM blower speed with dip switch setting on the control board. And yes, a 7 series would adopt best to all occasions. They are quite expensive, but worth the money especially after tax credits are applied.
The 7 series sometimes confuse sizing, a 3-ton 7 series would carry the same load as a 4 ton dual stage unit. In the monitoring we see a performance benefit of 22% versus dual stage units, so I become more and more a fan of them. Again, spendy, but worth their money.

Thanks for the advice. What about an equivalent in the climatemaster series? I hate to ask my HVAC guy to change to a series he may not have any experience with and me be the guinea pig for it. And does it make any difference if the loops are in a pond vs the ground?

Climatemaster does not have the variable speed pump on the market. Sure, you can use a tranquility 27, 4 ton seems good assuming your calculations are correct.

I tentatively agree with 4 ton. In a hot humid environment such as Memphis you definitely don't want to be oversized for cooling, so I might look for ways (envelope improvements) to shave load down closer to 3 tons

I'd rather see full load capacity closely match design cooling load, with part load operating with longer on-cycles the vast majority of the time for better dehumidification.

Still, it may well be that 36kBtuh gain translates to 4 tons owing to sensible heat ratio. Most systems provide only 9000 Btuh sensible cooling per ton, with the remainder going to latent cooling. Your load calc should break out the 36k into latent and sensible components...please post those.

30,500 sensible
and 5500 latent gain
Typically how much more would the water furnace be over the climate master? For similar tons.
Thanks

The ClimateMaster and WaterFurnace should be similar in price, its all going to come down to install and quality of materials and experience of installer. WaterFurnace just has more innovative products at this time. Climatemaster has plans to release a variable compressor system with Q Mode but everything I have heard says it is well over a year away while the WaterFurnace is available now.

edit....  in response to the comment on Climate master 27 above.... 

I'm guessing most installers using Climatemaster would be using the Tranquility 30 now?   The Tranquility 30 appears simlar to the 27 model, but with some efficiency tweaks and (or as a result of)updated controls... with integral water regulating valve or variable speed pump, as well as upgraded desuper heater controls... and more system monitoring and diagnostics on board.

Okay by beefing up the foundation insulation and reducing inside temp from 74 to 69(didnt notice how high it was before and that is usually what I keep mine at during day and 66 at night) I can reduce BTU loss to 42,000. Gain is 36,000. Could I go with a 3.5 ton climate master at this range? Thanks

Being 10-20% short for heating is OK, indeed often well-advised, given that strips can make up the difference during the few cold nights at modest cost.

3.5T is probably dead nuts on for the current gains. My only reservation would be that half ton models (2.5 and 3.5) are not two stage. Two stage systems do a better job at dehumidification at the part load conditions that obtain during all but the hottest weather. In addition, two stage systems are quieter and more efficient while in low stage.

The 4T offers an advantage of operating at about 2.75 tons in low stage, running longer, quieter and higher efficiency.

OTOH, carry further your load reduction work so that the 3T fits.