Is it worth upgrading a high efficeincy single stage to a multi stage?

[PHD112]

Here's the deal... we built our house a few months ago near Buffalo, NY (2,900 sq ft) and the builder put in a Lennox G51MP with coils, we opted out for a/c because they wanted something ridiculous for it. Well with warmer air approaching we're looking to install a/c now. A Lennox dealer gave us a decent quote on a 4 ton XC13-48. I had a Carrier dealer come out (I've used them in the past for an Infinity system at our previous home) and he quouted me high, because he said he wouldn't use the Lennox coil. He said with all the rebates (Gov & Carrier) I could get an Infinity ICS (100,000 BTU) and a 17 SEER 4 ton Infinity A/C for about $ more than the Lennox offer for A/C. The dilema is it worth going with the Infinity setup over just getting the XC13 put in? I don't know enough about HVAC to make an educated decision.

[BaldLoonie]

First, why won't he use the new Lennox coil?

How did he arrive at 4 tons for 2900 sq ft new construction in a mild climate? Seems like a lot if the house is built well unless it is all window.

Going from 92% Lennox to 95% 3 stage will have almost no energy savings. A few bucks a year probably. The 3 stage is for comfort only. Going from 13 to 17 SEER A/C in a cooler climate probably won't pay back very fast either. If you were in Florida might be worth it.

I'd find another Lennox dealer and see what just an outdoor unit to match the new coil and the needs of the house would run.

[PHD112]

Carrier guy says doesn't like matching Carrier to Lennox (figured a line of bull). Yeah I knew cost saving wise it isn't going to be a deal maker. The comfort thing is where it factors in, do you think we'd see a significant constant temp? Someone's always home so the thermostat is a 2 degree diff from day and night time, so no drastic preset temps, comes down to that blast of hot air versus steady. Does the number of runs play a factor on the 4 ton? We have 6 bedrooms (alot of kids). Just trying to decide if it's wise in the long run, as I'm not going to touch the system for a long time hopefully.

[beenthere]

The Carrier guy is right. Can't use a Lennox Coil with a Carrier condenser. And know how it will work.

Does sound like they are sizing by rule of thumb.

[Todd S 2]

Here's the deal... we built our house a few months ago near Buffalo, NY (2,900 sq ft) and the builder put in a Lennox G51MP with coils, we opted out for a/c because they wanted something ridiculous for it. Well with warmer air approaching we're looking to install a/c now. A Lennox dealer gave us a decent quote on a 4 ton XC13-48. I had a Carrier dealer come out (I've used them in the past for an Infinity system at our previous home) and he quouted me high, because he said he wouldn't use the Lennox coil. He said with all the rebates (Gov & Carrier) I could get an Infinity ICS (100,000 BTU) and a 17 SEER 4 ton Infinity A/C for about $2k more than the Lennox offer for A/C. The dilema is it worth going with the Infinity setup over just getting the XC13 put in? I don't know enough about HVAC to make an educated decision.

It's a shame that the builder had a HVAC guy put in a bare bones furnace in a brand new house. Unbelievable. You've got s**t now.
In my opinion, the furnace is the foundation to the system.
The Carrier guy doesn't want to use the Lennox coil because it interfers with the Carrier rebate program.
What to do? For the extra $$$, I would bite the bullet and put in the Carrier system. Maybe there is some value in the Lennox (unused) coil. Nobody wants the furnace.

[beenthere]

It's a shame that the builder had a HVAC guy put in a bare bones furnace in a brand new house. Unbelievable.


Standard building practice.

[tedkidd]

I put a 60mbtu 3 ton Hybrid Heat system into a bigger house than yours, but it is a zoned system. See pictures HERE (http://picasaweb.google.com/teddykidd/ACOMPLETEDPICTURES#). Four tons sound like they might be "playing it safe" with your equipment $ and energy $, unfortunately when you oversize comfort may also suffer.

I think going with Infinity is a really good idea for a lot of reasons. One is you can add the communicating zoning later if you really want to dial in control of the system. I've also installed the Carrier Internet SAM for this and another client.

Run this job through Home Performance with Energy Star. You'll get a comprehensive analysis of your home, a whole lot of consumer protection, and get the job done right.

You'll also get Cool Cash, the tax credit, a check for 10% from Albany (this rebate is funded by our electric bills) and the contractor will get 5%. The deal is such a win, win, win that once you know about it you'd have to be an idiot not to participate.

I'd consider coming to Buffalo, but only if you are willing to get Hybrid instead of straight AC.

[darmistead]

multi stage furnace & ac increases comfort and decreases cost of operation
recommend having load calc done before so it will be properly sized

[PHD112]

Thanks to everyone that's responded, I really appreciate it. Yeah it's standard builders practice to give you bare bones then offer to upgrade it for twice as much if you want to a dealer. That's why I'm even contemplating it, because the furnace is just a standard one. Don't plan on moving in the next 20 years so in it for the long haul. Does wanting to finish my basement sway my choice either way? I don't want to do supplement heating, I'd rather tie into the current system and add zoning like someone mentioned. Or does the whole basement not factor into the furnace as much as the size of the duct work runs. Again thanks to everyone, really glas found this forum.

[BaldLoonie]

Unless the ducts were designed for zoning, sometimes doesn't work out too well since you are trying to stuff all of the air into part of the ducts. Multistage equipment does help, especially if you got the 3 stage Infinity system and their zoning system.

I agree, didn't read carefully enough that it was the Carrier dealer who didn't want to use the Lennox coil. So unless you really want to spend the bucks replacing everything (weigh the costs carefully) I'd stick with Lennox dealers to match the coil.

[dash]

I put a 60mbtu 3 ton Hybrid Heat system into a bigger house than yours, but it is a zoned system. See pictures HERE (http://picasaweb.google.com/teddykidd/ACOMPLETEDPICTURES#). Four tons sound like they might be "playing it safe" with your equipment $ and energy $, unfortunately when you oversize comfort may also suffer.

I think going with Infinity is a really good idea for a lot of reasons. One is you can add the communicating zoning later if you really want to dial in control of the system. I've also installed the Carrier Internet SAM for this and another client.

Run this job through Home Performance with Energy Star. You'll get a comprehensive analysis of your home, a whole lot of consumer protection, and get the job done rig
You'll also get Cool Cash, the tax credit, a check for 10% from Albany (this rebate is funded by our electric bills) and the contractor will get 5%. The deal is such a win, win, win that once you know about it you'd have to be an idiot not to participate.

I'd consider coming to Buffalo, but only if you are willing to get Hybrid instead of straight AC.


Return drop to filter ,in the pics,is a very restrictive fitting.

Full size with vanes would be better.

[im4snow2000]

I put a 60mbtu 3 ton Hybrid Heat system into a bigger house than yours, but it is a zoned system. See pictures HERE (http://picasaweb.google.com/teddykidd/ACOMPLETEDPICTURES#). Four tons sound like they might be "playing it safe" with your equipment $ and energy $, unfortunately when you oversize comfort may also suffer.

I think going with Infinity is a really good idea for a lot of reasons. One is you can add the communicating zoning later if you really want to dial in control of the system. I've also installed the Carrier Internet SAM for this and another client.

Run this job through Home Performance with Energy Star. You'll get a comprehensive analysis of your home, a whole lot of consumer protection, and get the job done right.

You'll also get Cool Cash, the tax credit, a check for 10% from Albany (this rebate is funded by our electric bills) and the contractor will get 5%. The deal is such a win, win, win that once you know about it you'd have to be an idiot not to participate.

I'd consider coming to Buffalo, but only if you are willing to get Hybrid instead of straight AC.

Tedkidd....I checked out the pics on your website. Nice pics. When you sprayfoam box bands (or any area where the foam stays exposed) do you have to go over the cured foam with any type of fire-retardant...assuming the foam will NOT be covered with drywall, etc??

Didn't mean to hijack this thread.....I tried to send a PM to you, but no go.

[tedkidd]

IM4SNOW - emailed u

Return drop to filter ,in the pics,is a very restrictive fitting.

Full size with vanes would be better.

Ahh, the beauty of Infinity. Tells you static in all stages so you don't have to wonder about the system being too "restrictive".

Really freaky part is I don't think these units, smallest available, never go to high fire. Actually concerned lack of static, particularly on low furnace and low heat pump stages, might cause temperature imbalance issues, but very happy clients seems to allay that concern.

(HO edited post to indicate 100mbtu recommendation from Carrier Dealer in Buffalo, guess that fitting would be restrictive for THAT!!! Brand new 2900 sf house that needs 100mbtu in this climate is a real pos!!

Is your dealer calling your brand new house a pos, or just quoting based upon straight swap without load calc?

Do you really want to pay the equipment cost penalty, comfort penalty, air flow penalty, and energy penalty for that huge furnace for the next 15 years? If you go for zoning (to fix comfort problems of poor equipment match) your options are severely limited with an over sized furnace.)

[amd]

I would just get a basic lennox condenser - 13 seer, 14 max.

If you want lower heating capacity for mild weather, consider getting adding a heatpump; if setup correctly, the furnace will take over below a specified outdoor temp. (outdoor temp sensor and dual fuel t-stat required)

Don't let the contractor oversize; if a 3 ton (3.5 max) condenser can't be matched with the existing coil, change it out.

Consequences of oversizing:

- High energy consumption
- Poor dehumidification
- Excessive noise (especially if the builder cheaped out on ductwork)
- Uneven cooling due to short cycling

[PHD112]

He's gotta be basing it on a swap, it's an energy star certified home. If I decide to go with the Infinity you can bet they will be doing a load calc. The 4 ton A/C was my first inclination that they're guessing/estimating on equipment.

[tedkidd]

If it's a 2900 sf energy star home with a >2000 blower door number, I would put money on a 60mbtu mvc060 and a 3 ton heat pump. You'll need the 4 ton coil to qualify the system for the 10 % back from Albany, which given the investment, particularly if zoning, will be a nice chunk of change.

[jw4335]

Not worth changing furnace. Not going to save you enough money. You will get a little more comfort

[tedkidd]

Not worth changing furnace. Not going to save you enough money. You will get a little more comfort

Please show me the diagnostic testing, energy bill analysis, customer comfort interview, and cost benefit analysis you performed to arrive at that conclusion.

[gary_g]

Please show me the diagnostic testing, energy bill analysis, customer comfort interview, and cost benefit analysis you performed to arrive at that conclusion.

Not to defend JW4335, but....



Going from 92% Lennox to 95% 3 stage will have almost no energy savings. A few bucks a year probably.

Take care.

[tedkidd]

... "few bucks a year" when apples to apples.

How about when going from a grossly over-sized single-stage that may never reach the highway (condensing sweet spot), to a properly sized multi-stage that might actually come close to laboratory efficiencies?