new build hvac advice

peony23January 15, 2014

I was hoping the experts would weigh in and give me their opinions.

Our new build is in Maryland, single story 3400 sq ft, finished basement 1400 sq ft. We have 2x6 construction, upgraded insulation, good windows. We're on propane. HVAC recommended is Lennox 2 zone, 80K btu, 92% efficiency, 13 seer, 3 tons. Is this sufficient or is higher SEER and efficiency worth the added expense?

Thanks in advance.

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tigerdunes

I would like to see some model numbers...

Since you are on propane, I would want higher furnace efficiency, two stage var speed plus add a high eff heat pump to help offset the expensive propane.

Now is not the time to go low end builder grade.

Not a fan of Lennox either.

IMO

    Bookmark   January 16, 2014 at 7:34AM
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peony23

Thanks, tigerdunes.

I don't have model numbers yet, just the general specs. The builder uses York for his higher efficiency systems. Do you like those any better? His thinking is they're all pretty much the same, but we know better.

    Bookmark   January 16, 2014 at 8:13AM
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mike_home

Is the contractor proposing a single furnace and condenser with two zones, or two furnaces and two condensers?

Is the house 3400 sq. feet, or is it 2000 sq. feet plus a 1400 sq ft. finished basement?

    Bookmark   January 16, 2014 at 9:03AM
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peony23

Thanks, tigerdunes.

I don't have model numbers yet, just the general specs. The builder uses York for his higher efficiency systems. Do you like those any better? His thinking is they're all pretty much the same, but we know better.

    Bookmark   January 16, 2014 at 11:03AM
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peony23

Mike, there are 2 units, with the specs I've mentioned. Total 4800 sq ft.

    Bookmark   January 16, 2014 at 11:06AM
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tigerdunes

Deleted....

This post was edited by tigerdunes on Thu, Jan 16, 14 at 16:02

    Bookmark   January 16, 2014 at 11:17AM
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mike_home

For Tigerdunes,

The OP said this a 3400 sq. foot single story house.

"We have 2x6 construction, upgraded insulation, good windows"

This is better than typical construction. How much insulation will be in the attic?

The contractor is proposing 160K BTU heating and 6 tons for cooling. In my opinion this would be over sized for typical 2X4 construction and insulation in your climate. It is much over sized for what you are building.

Has the contractor done a load calculation? If so has he factored in the upgraded construction and insulation?

    Bookmark   January 16, 2014 at 2:03PM
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peony23

Tigerdunes, can you please repeat your recommendations for the heat pump/propane backup system? I'm talking to the builder about that setup, and it might be the one to go with. Thanks.

    Bookmark   February 4, 2014 at 8:02PM
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tigerdunes

Because of the propane, you want top of line most efficient furnace possible.

While Lennox would not be my choice, I will assume you want recommendations for that brand.

SLP98v furnace up to 98% eff
XP21 heat pump
Best matching Lennox coil
Lennox thermostat
Filter box

I assume your home is being built over a crawlspace.

Rather than 2 systems, I would consider dividing home into 2 zones and use a zoning control for one system.

Insist on load calc both heating and cooling. Get it in writing. Assuming your home will have excellent building and insulation qualities, you definitely don't need 160 KBTUs of heating.

IMO

    Bookmark   February 5, 2014 at 7:28AM
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peony23

Thanks, tigerdunes. I started talking to the builder about a heat pump only after you mentioned it. So thank you. The house will be one-story but with a 40% finished basement, so 3400 1st floor, 1400 sq ft finished in the basement. We are planning 2 zones, but I'm don't understand your comment about zoning control for one system. We will get the load calculation you recommend, and the 160K BTU was for propane furnace, so we'll see what's needed with a new system.

I know in the past I'd heard heat pumps were not really recommended north of around North Carolina. We're mid-atlantic, and we're getting hammered by cold right now. Is a new generation heat pump really the best way to go for this climate? We won't ever have natural gas piped in to this community, so always propane as backup.

Thanks again.

    Bookmark   February 5, 2014 at 6:49PM
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tigerdunes

Lots of negatives in the past about heat pumps. No longer true though and in your case with propane fuel, today's high eff heat pumps is your only choice to leverage electric versus more expensive propane fuel.

What is your electric cost? What is current cost of propane? You have been following the propane shortage story along with what has happened with pricing?

I would want a dealer with demonstrated experience in zoning and purchase just one system to handle the heating and cooling of your home.

If this was my home, I would be looking at geothermal or a Carrier Greenspeed system.

IMO

    Bookmark   February 6, 2014 at 6:18AM
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peony23

Thanks again, tigerdunes. Geothermal is out of the budget. The builder's hvac guy uses Lennox, so I guess that's what we get. I'll certainly ask about any other options. We're looking at an addional $4500 from furnace to heat pump--does that sound about right?

    Bookmark   February 6, 2014 at 9:24AM
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tigerdunes

You want both. HP and furnace and zoning controls to handle your zones...sounds like 3 zones...

Not sure if we are on same page...

IMO

    Bookmark   February 6, 2014 at 9:50AM
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peony23

Thanks again, tigerdunes. Geothermal is out of the budget. The builder's hvac guy uses Lennox, so I guess that's what we get. I'll certainly ask about any other options. We're looking at an addional $4500 from furnace to heat pump--does that sound about right?

    Bookmark   February 6, 2014 at 10:49AM
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peony23

Sorry, don't know why that posted twice.

Trying to get on the same page, tigerdunes. To sum up my understanding, we're looking for a heat pump with propane back up, so separate (smaller?) furnace, and AC that's in the heat pump. Correct? What are the main differences between the Lennox units and the Carrier that you recommend? Or, what should I look for in any unit that we go with?

Thanks again.

    Bookmark   February 6, 2014 at 11:16AM
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peony23

Sorry, don't know why that posted twice.

Trying to get on the same page, tigerdunes. To sum up my understanding, we're looking for a heat pump with propane back up, so separate (smaller?) furnace, and AC that's in the heat pump. Correct? What are the main differences between the Lennox units and the Carrier that you recommend? Or, what should I look for in any unit that we go with?

Thanks again.

    Bookmark   February 6, 2014 at 11:17AM
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tigerdunes

"Thanks again, tigerdunes. Geothermal is out of the budget. The builder's hvac guy uses Lennox, so I guess that's what we get. I'll certainly ask about any other options. We're looking at an addional $4500 from furnace to heat pump--does that sound about right?"

I can not help on the pricing because you never provided the baseline Mdl numbers your dealer initially quoted you. Nor have you provided the Mdl numbers to cover the extra $4500.

Carrier has a low temp heat pump called GreenSpeed. Suggest you go their site and read up on it. It is relatively new but anecdotally a successful introduction. Pricing would be up to 50% higher than a conventional high end DF furnace/HP system.

As far as Lennox, I was talking about one correctly sized system with zoning controls.

IMO

    Bookmark   February 6, 2014 at 12:02PM
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peony23

Tigerdunes, still trying to get questions answered by builder. He's very much a Lennox guy. What are the negatives for Lennox? What problems have you encountered? Thanks again.

    Bookmark   February 19, 2014 at 11:44AM
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tigerdunes

It's not so much negative about Lennox but I think Carrier and Trane along with sister companies are better especially with their HPs. But I won't quibble over the models of Lennox furnace and HP that I gave you in older post.

If you go with zoning control off one system, you need to qualify builder/dealer in this area of expertise. Zoning is not for the inexperienced.

IMO

    Bookmark   February 19, 2014 at 12:00PM
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peony23

Tigerdunes and all pros

Builder set on Lennox heat pump, model 13HPX. Online reviews are mixed, at best; warranty looks to be minimal. Your input needed re other Lennox models, sort of least of evils option. Again house is 3400 main level, 1400 basement, 2 zones.

Thanks

    Bookmark   March 24, 2014 at 3:19PM
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tigerdunes

13HPX is low end cheap POJ HP made South of the Border. Your dealer is looking out for himself, certainly not you. XP 17 minimum depending on propane Mdl furnace. What furnace does dealer plan on using?

IMO

    Bookmark   March 24, 2014 at 3:51PM
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peony23

I don't know furnace model yet, some other Lennox I'd assume. Anything I should request?

    Bookmark   March 24, 2014 at 5:20PM
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tigerdunes

Yes, tell dealer to hit the road and get another one involved who is halfway interested in looking out for you. This dealer/builder is certainly not.

Go back and look at my original list. That is your starting point. At the very minimum, I would want a two stage var speed 95%+ eff furnace model.

IMO

    Bookmark   March 24, 2014 at 6:22PM
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