[morgaine300]

I'm currently in the mists of trying to purchase what is now probably going to be a heat pump. Trying to do some research which is raising more questions. Also have a salesman who isn't explaining things well & is now playing games with pricing. (I've got a call in to another guy who hasn't called back yet, but holiday weekend & all that.)

So I'll probably be back w/lots more. :-)

Let's start with this. Originally from some info over the phone the guy said a 2 ton would be appropriate for the house. Now that he's been out here, he finds that I have either a 2.5 ton (according to my brother's memory) or a 3 ton (my memory) blower on the furnace. If there's more than one blower, couldn't tell you what he's referring to. Because of this, he now says it should be a 2.5 ton heat pump. I think the implication was that a smaller tonage heat pump wouldn't work right with the furnace. So the question is whether he's right -- would a 2 ton somehow be inefficient or whatever, or hurt for some reason?

While I'm at it, the ~price from on the phone to when he was here went up about $500. This may be very dependent on area, but does that sound reasonable going from 2 ton to 2.5 ton?

My brother also wondered if the speed of the blower can be changed, either through control in the thermostat, or simply a setting somewhere on the furnace. The book says it's a Bryant 383KAV Series H&J.

Just for reference, stuff about the area, weather, etc is in another post:
https://www.askmehelpdesk.com/heatin...-c-224022.html
And it's an 1100 sq ft house main floor, story & a half cape cod -- but I've got everything in the attic closed off. My brother thinks I oughta err on the side of a little too big in case I ever want to use it up there. (Doubtful in my mind. It's storage.)

[hvac1000]

First. The size of the heat pump that you need can only be determined correctly buy doing a manual J.

The duct size you need can only be done with a manual D.

You never concern yourself if the furnace blower is not big enough. If it is not you change it.You size the furnace blower for the size of heat pump you need and how many CFM you need across the coil so the heat pump operates correctly.

500.00 up charge to get a two and a half ton unit instead of a two ton unit is reasonable.

The speed of the blower can be changed as long as it is a multi speed blower motor and usually they are.

If the company's you are dealing with do not know what a manual J is then I would move on to another company that does. A unit to small OR to large can be a problem either way. That is why you need a manual J done so that the correct size is a known entity and mistakes will not be made.

There is really is no guess work when it comes to sizing a system. Guessing can cost you too much $$ on the install but worse than that it can cost you in your monthly utility bill.

Contractors that guess on size has caused so many problems for people it gives the HVAC trade a bad name.

[morgaine300]

Thanks for the response. I of course have no clue about a manual J or D. But the sales guy never looked anything up in any manual, if that's what you're referring to. He may have while we were on the phone, but not when he was here. He just saw the furnace and then changed it to a 2.5 ton. (I will ask about him about this.)

What I do know is that my furnace is only 7 years old and I wasn't exactly intending to replace it. So is this something that can simply be replaced inside/outside the furnace (wherever the heck it's at)? Or I guess I should be checking if it's multi-speed. (I didn't have much luck when I googled my furnace for info.) We're replacing the coil, I know, cause the thing's 35 years old like the A/C is.

[hvac1000]

So is this something that can simply be replaced inside/outside the furnace

I would not say simply but it is done every day. It does take some work.

I guess I should be checking if it's multi-speed

That is the contractors job. He should state weather or not the blower you have will work correctly with the new unit. (I believe it will)

The coil,outside unit AND the copper line set that connects the two.

Here you go. Manual J and the reason for it.

The Air Conditioning Contractors of America (ACCA) guidelines for sizing HVAC equipment, ACCA Manual J Residential Load Calculation, enables contractors to estimate heating and air conditioning loads more accurately. Using Manual J, a contractor calculates heat loss from the building through walls and ceilings, leaky ductwork, and infiltration through windows, doors, and other penetrations as well as heat gain into the building from sunlight, people, lights and appliances, doors, walls, and windows, and infiltration though wall penetrations. Design conditions for the area are also used as inputs into load calculations.

Air infiltration measurements must be estimated unless a blower door test is performed. The use of blower door test results will provide more accurate sizing calculations at a slightly higher design expense. Again, increases in design costs can be offset by decreased equipment size which lowers initial cost.

By properly sizing HVAC equipment rather than using rules of thumb, smaller systems can often be specified and, hence, initial cost is reduced.

Proper HVAC sizing is an essential step in the efficient operation of HVAC systems. A right-sized system will operate for long periods (rather than frequently cycling on and off), resulting in the optimum equipment operating efficiency.



Proper HVAC sizing can reduce short-cycling of equipment, resulting in longer equipment life and better control over indoor environmental conditions



And now you have the real story of what a real HVAC company should do and the reasons they should do it.

[morgaine300]

Even though I don't exactly understand all this, it does at least give me stuff to ask about -- either to the first sales guy, or to the next one. I know more what to ask about now, which I think will help a lot. My brother has talked about the cycling too often thing.

I also have questions on thermostats. If you'd rather this be a new thread, just say so or feel free to move it.

This guy's also trying to get me to get this Honeywell VisionPro, and now that I've looked it up, looks like their top-of-the-line. Figures. However, it also looks like only the top ones are going to work, partly cause it's a heat pump. But also the features. I don't understand what some of the stuff is. They're all programmable, but I don't care between the 7 vs 5-2 etc. But I want to have manual override to switch off to the furnace. (I don't care about other features unless there's something really useful that I'm unaware of.) I also dislike the touch screen things. Any suggestions?

My brother seems to think I could install one myself. I've done phone lines & other electric stuff, but the more I look at this, the more I seriously wonder about that.

Thanks much for your time.

[hvac1000]

The Honeywell is top of the line and I recommend it.

To turn the furnace off just pull or flip the disconnect switch on the furnace or your electric panel.

A manual comes with the thermostat.

Here is one for you.

http://customer.honeywell.com/techli.../69-1896ES.pdf


http://customer.honeywell.com/techli.../69-1894ES.pdf

[morgaine300]

I think you missed the point. :-) I'm trying to find if there's a less expensive model that'll still do what I want it to, not trying to find the best thing I can possibly get.

As for the furnace, not trying to turn it off -- I want to be able to manually force it on in place of the heat pump if I so choose. (The one thing I didn't like the sounds of with a heat pump is that it heats slow, and there may be times when I want it to heat quick, which the furnace will do. I heard I do this from the thermostat.)

[hvac1000]

I think you missed the point. :-) I'm trying to find if there's a less expensive model that'll still do what I want it to

Then go here and look around. Then price the units on the web.

Catalog

Yes a heat pump does heat slow especially if it is real cold outside.

Depending upon the thermostat you pick you can bring on emergency heat or the second stage heat which will bypass the heat pump.

Good luck.

[morgaine300]

Got one more tiny question. I've been looking at thermostats half the day trying to figure them out. I think the FocusPro would do very nicely. (Even think I found one PRO version that would work that just has old-fashioned slide buttons -- I actually prefer the old, non-fancy way of doing stuff. ;) ) I did manage to figure most of it out.

But the one tiny question: the 2heat/1cool thing, what they're calling "multi-stage," is what I want for the auxiliary heat, right?

And then I will stop bugging you for the moment. :D

That other sales guy called me today and I talked to him for a bit. Between what you've told me and talking to him, I actually feel a lot clearer on some things now and don't feel like I'm grasping blindly. He's coming Monday & I feel ready for him. (And ready to email the other guy back on his really lousy quote he sent.)

So thanks much!

[hvac1000]

If you have this a heat pump system with a electric or gas furnace you will need this 2heat/1cool type of thermostat.

I have a habit of only buying the top of the line thermostats for my customers many years ago. Pick one out of the bunch you can afford.

[morgaine300]

Hey, thanks for all the help. I'd leave another greeny for the extra time, but haven't spread it enough. :-) Saw the new sales guy today, who sounded way more intelligent. He of course raised some new questions, but I'll start a new thread this time...

[KISS]

Here is a simple explanation for "stages", without using a heat pump, but rather nat gas/AC.

Stage 1 heat: Burners come on at a low flame.
Stage 2 heat: Burners come on at a high flame, One way that this happens is if the difference between the temperature measured and desired is large.
Say it's 50 deg in the house and your set poit is 80 F. You will get high heat. If the difference is small, say 3 deg, you;ll get low heat.

Stage 1 cool: A lower outdoor fan speed is used.
Stage 2 cool: The fan runs on a higher speed.
Again determined my the temperature difference for the most part.

The system must be able to support these modes.

An option to consider is the possibility of dual fuel. You can combine a heat pump and a Nat gas furnace, for instance. Emergency heat for a heatpump system is usually electric, but nat gas can be used.

[morgaine300]

Stage 1 heat: Burners come on at a low flame.
Stage 2 heat: Burners come on at a high flame, One way that this happens is if the difference between the temperature measured and desired is large.

I thought the 2 stage was 2 different types of heat. (Like I've seen the example of the second type being strips inside the furnace, whatever the heck those are.) Am I confused?

An option to consider is the possibility of dual fuel. You can combine a heat pump and a Nat gas furnace, for instance. Emergency heat for a heatpump system is usually electric, but nat gas can be used.

Yes, this is what I'm doing. I already have a gas furnace, so that'll be my auxiliary. And around here, we're under 25-30 degrees half the winter. At least a furnace is easier to understand -- it has gas, it makes heat, it blows it through the house. This whole heat pump thing is just weird to me. But I'm now learning about pulling hot air out of cold air, which I guess is similar to pulling a rabbit out of a hat. Just what an accountant wants to know -- physics.

[KISS]

This is a complex question to answer, so I may have to come back to this or have some help.

First some basics:

HEAT PUMP

It's similar to an air conditioning unit. If you go outside when the AC is running, the outside unit blows hot air while the inside is cold. If you reverse the lines to the compressor, the reverse becomes true. Hot air inside, cold air outside.

The heat pump efficiently moves heat from one place to another. However, when the temperature gets too low, it doesn't work very well. It doesn't work at all when one side freezing. Hence the controls are a bit more complex: there is the need for defrosting, a reversing valve and some other means of supplementary heat when the temperature gets too low. In other words the heat pump is locked out and usually the more expensive resistive heating is used. The "heat strips".

FAN CONTROL

In a gas system the furnace controls the fan. Once the burners ignite and get hot enough, the fan comes on and once the burners go off the fan goes off sometime later to extract more heat.

In a Heat Pump or AC system the thermostat controls the fan. In other words the fan and the compressor come on and go off at the same time.

In a heat pump system with electric strip heat backup, the compressor runs most of the time, but when the diference between the setpoint and measured temp is large the strip heaters can come on in addition to the heat pump. Eventually the heatpump is locked out due to the outside temperature or freezing coils.

In a heat pump system with natural gas backup, the traditional dual fuel setup, once the gas kicks in, the Heat pump MUST turn off to avoid damage.

Thus "dual-fuel" means the thermostat must know if the backup heat is electric or gas and control it accordingly. The thermostat you pick must be capable of controlling a dual fuel system.

With "Emergency heat", you have the option to allow or dissallow it, since it's extremely expensive and heat pump thermostats have this capability.

Hopefully, I'll dig up some better info on staging.

[KISS]

Back to stages:

Stages mean something is different. Whether it be burner BTU's, gas, oil, electric, heat pump or whatever. In order to have emergency heat with a heat pump, you need at least 2 stages of heating.

Here is a direct quote from one of the Vision Pro Install manuals:

Heat Pump Temperature Lockout (with fossil-fuel backup): If the thermostat is installed with an optional outdoor sensor, you can select a compressor lockout temperature (Function 0350). When the outdoor temperature is below the lockout temperature, only the auxiliary heat operates. When the outdoor temperature is above the lockout temperature, only the compressor operates.

Heat Pump Temperature Lockouts (with electric heat backup): If the thermostat is installed with an optional outdoor sensor, you can select a compressor lockout temperature (Function 0350) and/or an auxiliary heat lockout temperature (Function 0360). When the outdoor temperature is below the compressor lockout temperature, only the auxiliary heat operates. When the outdoor temperature is above the auxiliary lockout temperature, only the compressor operates. If the outdoor temperature is between the compressor and auxiliary lockout temperatures, both the compressor and auxiliary heat can operate.

[morgaine300]

Sorry I didn't come back to say thanks for the info. Been really, really busy recently.

I also admit I've been avoiding this cause I'm just SO tired of this stuff right now. Any time I have to deal with buying something new, especially something expensive, and especially something I know very little about and have to investigate... I just get really sick of it and wish it would go away. I'm trying really hard right now not to just call "whoever" and say "just get over here and replace this thing." :-) Of course, it's not going to go away, and I'm trying not to rush it.

Would it be tacky to ask whether a quoted price seems reasonable? I also don't know how much this varies by region, if it does.