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Need to do a proper load calculation to determine the correct size, but a 2.5 or 3ton for downstairs and a minisplit for upstairs bonus room doesnt sound unreasonable. You have a newer house that...

The ManJ looks good to me and is most likely correct.

1000sqft per ton on a 1965 house in Dallas is half the "standard size". I'm not sure that you will find a contractor willing to stick his neck...

Without a City/State or knowing the age of the house it's impossible to even guess roughly what size might be correct for your house. Big differnce between 1960's house in TX vs brand new...

It's best to have total static pressure MEASURED to see how it's actually performing. Test, don't guess.

It seems most furnaces in our area made after 2000 use separate high/low depending if Y is energized. Older furnaces it's just a tie point. Goodman was late to the game, not sure if their current...

Refrigerant does not have a fixed capacity of heat it can pull away from the coil. Higher suction pressures due to high blower speed will normally get more capacity out of the compressor. The...

You don’t even need a relay. Wire Y1 straight to condenser, Y2 to Y on the furnace board. G will bring on low speed blower with the cool call, Y2 will energize Y on the furnace board bringing on high...

Think about what happens if you are a *little* short on heat/cooling.
Your house wont suddenly convert to an igloo, it will just be a few degrees below your desired setpoint while you have a...

I contacted the manufacturer about a test sample, they wanted over $100 for the "discounted" test device. A simple 60 second delay that is found OEM in most modern furnaces saves just as much money...

FWIW I have a single 2 ton for my 1600sqft house in OKC. MUCH hotter than MA. My AC runs less than 1/2 the time when it's 85F, Above 95F it runs 100%.

You have NO AC now? I can't see a house that...

It's a CYA thing. Contractor wants to make 120% sure that the system will keep up even when well above design conditions. The last thing he wants is a call that the system won't keep up.

Glad it all worked out. Surprised they went up a full ton in cooling size instead of reducing the load 0.1 tons. The nice thing about VS equipment is is ability to run at just the right capacity.

Here in Oklahoma we have3 be been through a month of cool wet weather
Not cold enough for heat or warm enough for AC. Record rainfall for the month. Wishing I had one of those ultra - aire units.

A 4 ton should be PLENTY for 2600sqft built in 2002. May even need less. A load calculation will let you know.

Don't over think it. Sqft of entire house? Total tons of all systems?

I may have said too much already. Hopefully your AC guy can figure it out.

Be sure everything works and the condenser runs the "right direction" in heating and cooling. Have him verify emergency...

Agree with others, the "up to" SEER is very different than delivered real work performance. If you aren't getting at least 700sqft out of each ton of AC, some house/ductwork tightening will help a...

The jumper from W1 to Y brings the condenser on in heating mode, has nothing to do with 2 stage heat pump.

Only 1 out of 10 programmable thermostats is set correctly. Most are simply left on "hold" mode.

A 2.5 ton would probably do the job if the insulation is good and the house is tight. You *may* loose a few degrees on the hottest afternoons, but would get excellent humidity control the other 98%...

A properly sized setup should run no more than twice an hour and still be able to keep the temp within 2 degrees of setpoint. Oversized systems will have to let the temp droop more than 2 degrees if...

If 76k wont heat 3200sqft @ a 13f design temp then you need to find and fix the leaks in the house. 76k is a LOT of heat leakage, if you have MORE than that, then the large leaks should be easy to...

Look at KWH and Therms, your use probably dropped more than 10%. A lot of utilities have rate increases in the past year. What city is the house located? I would have used the extra $$ to split...

What happens if the system can't keep up on those design days? The temp will slip a few degrees, thermal mass will normally prevent the house from getting too hot. Humidity will be low due to LONG...

Double RPM is 8 times the HP. It's CUBED, not squared.
http://www.freecalc.com/fansfram.htm

I doubt he'll even spend the $$$ on the motor unless the original doesn't provide enough CFM to stop the coil from freezing up.

I'm sure it can be done, it will just be noisy and inefficient. Large blades moving at slower speeds tend to be more efficient than small blades turning at high speeds. But larger wheels cost more as...

Where I'm CA are you? If heat isn't used very much I question the need for a 70k furnace.

Probably has a 10x7 or 10x8 wheel, getting 1600cfm through it at a decent static pressure using any type of motor is gonna be fun... 1600cfm normally needs at least a 10x10 wheel.

4ton cool/70k heat is way overkill for a typical 1307sqft house. Unless your house is extremely leaky or in an extreme part of CA, it shouldn't need that large of a system.

70 degree DRY or HUMID air?

Why no backward inclined blades? That's where the REAL savings are, forward curved blades are only about 65% mechanically efficient vs 85% for backward curved.

With a low enough static enough pressure the larger motor running at 1075RPM may deliver the 1600CFM. Keep in mind that lower static = higher airflow, but requires more HP from the motor to keep the...

117f is an OCCASIONAL temp, what is design temp for your area? Dropping for a 5ton down to a 4ton (20% reduction) will save you the same as a 2 point SEER increase (20% increase). Don't go too small...

A 100k furnace is a complete waste for Oklahoma. If you can cool the house with a 5 ton AC, you can heat it with an 80k furnace.

60k furnace with outdoor temps below zero. Must be either a small or tight house.

Says a lot about how stupid a 100k furnace looks in a climate that doesn't even get below freezing. We have a...

You have to be less than 30% oversized on order to have the ideal high/low switching during cold weather. This means a furnace that's about 1/2 the size typically installed. How many furnaces have...

Old thermostats had a 1 or 2 degree differential to kick in 2nd stage. Newer stats are normally timed and watch how quickly the temp rises with just stage 1 calling. If the difference is over 3...

Looks like a simple amp clamp. Make sure the TED knows it's hooked to a 240v source. AC units average about 1,000W per ton @ 95f outdoor temp. Newer units less, older units more. Cooler temps reduce...

Most 2 stage furnaces have low fire thats about 70% of full capacity. Most furnaces are oversized by at least 30% so the 2nd stage never kicks in unless the system is recovering from setback. The...

Want reliability? Install BASIC models that don't have ECM motors or fancy control boards. Correctly size them with proper airflow and heat exchangers/compressors will last a LONG time.

I'm on...

Silly car manufacturers developing ideas to save MPG when all they have to do is add a magnet to the fuel line. The amazon reviews are mind boggling, people actually believe it works...

You can buy some of those gas saver magnets that attach to your fuel line.... ...

2200/4.5 = 489sqft per ton. Agreed it looks like a "reverse engineered" load calc to hit 500sqft per ton.

Modulating furnace with PSC? I'm surprised they can get blower speed low enough when at minimum firing rate.

udarrell I doubt his original system was delivering 4 tons, much less 5. Most likely sized "500sqft per ton" but actually needs much less.

It's all good. Every time they bump the tread we call out the product...

Going from a 5 ton to a 4 ton will save 20% on your bill. Most of the time you won't notice the smaller unit since it's rare to find a 5 ton system that actually delivers the full 2,000cfm. Most are...

Replacing the fan relay with a 20-110 sequencer accomplishes the same thing.

There you have it. Out of the 3.5tons on your current system you may only be getting 70% or 2.5 delivered tons.

My house is not super tight but I have fixed all the big leaks. Leaks are easier to...