OT Heat Pump

more questions

Bill Tindall, E.Tn.

I have been traveling with my wife on a two or three week trip and needed to turn on the heater a few time while on the road, because we used to turn it off when not needed.

Does it get lonely? When you are gone for 3 weeks, or even two days, and especially in the winter, shut off the water supply and turn off the water heater. It will get over being unused and return to service with hot water within an hour after returning.

yup it did

Mike L

I never turn off the water while on travel. I do have sensors that will shut off the main water supply in the house if they detect a leak.

The heat or AC turning off was just because I it was a thing I have always done. I had a freezing snap come early (sort of like this year) while we where gone. I went into the app turned the heater on to 50 and let it go. Sometimes old habits die hard.

With this heat pump it seems I will have to change the ways I do things.

Update sort of

Mike L

I had my wife get me the model number of the current T-stat. Seems the heat pump we have has emergency heat, but it was not select able on the T-stat. Before I had left I was looking at getting another T-stat so I took a picture of the wiring so I could figure out which model I wanted to replace it with. It is wired for electric backup heat.

I had my wife reprogram the T-stat to say it had backup heat, and it seems to be working better now. I am not sure if the T-stat is going bad or the previous owner turned it off or what.

If it is cold tomorrow morning or doesn't appear to be working correct we purchased a home warranty that will take care of it for us.

Thanks for the reply's

Mike

A couple of more thoughts.....

Barry Irby

Financially it makes very little sense to turn the unit off with the outside temp is comfortable, unless you open the windows. I think most people no longer open their windows. Allergies, pollen, dust....you know. But, without the windows open there is very little heat loss or gain in mild weather and thus costs very little to let the heat pump do it's thing. At that point it is screamingly efficient.

Some of my discussion above may have been dated. The efficiency of the equipment keeps going up. Thermostats are more sophisticated. For example, it used to be that if the power flickered, you had to start all over and reprogram. Some of them have batteries and the early ones of those required reprogramming when you replaced the batteries.

I am turning into an old fuddy duddy and resistant to change. WiFi smiphi. OTOH, my son just bought a new house and the other day drove away forgetting to close the garage door. It stayed open all day and luckily nothing bad happened and nothing was missing. With the right controller on the door he could have checked on it from anywhere and closed it. That would require remembering to check. Or perhaps, they could build in a really useful feature and have it notify you the door is open.

I am a fan of SIMPLE. Many of the Smart Home features either failed or were ignored after the fad wore off.

One of the things Bill mentioned that really is a good idea is to turn your water supply valve off when you leave for days. You should also have "burst proof" supply lines on your washing machine. An insurance exec told me they had 200,000 house insured in VA and they had a hose burst every day on the average and that the average cost was about $6,000. They always burst soon after you leave to go somewhere. And you should have a drill like a fire drill on how to turn the water off. I told every family I did an inspection for where the valve was and how to operate it. It is amazing how many of them ignored me and how many were baffled. Some of them did not know you COULD turn the water off and were unclear on why.

As a fan of simple I like tried and true stuff and middle grade stuff. I tend to stay away for the exotic stuff. They make heat pumps that run at variable speeds and are extremely efficient. The problems are that they are very expensive and when they break the repair tech says things like "Wow, I ain't never seed one of these before." I think you are better off spending the extra money on improving the energy performance of the building. Spending a $1000 on attic insulation might save you more money than the fancy equipment.

Re: yup it did

Walter Ahlgrim

In general most HPs are sized for the cooling load and the emergency heat coil is sized for the heating load. HPs have a lower capacity to extract heat as the outdoor temp falls at some point more heat escapes your house than the HP can extract from the outdoor air at that temp. This is your houses balance point. Every house and it HP will have a different balance point temp. A common myth is that the HP is less efficient (BTU per dollar or COP) than the E strips at this point it is not true. Generally the COP is still 2 so whatever heat the HP can extract it is still saving you money to let it run at the same time as the E strips. Most systems still have a COP over 1 at -10°F. I have been searching for the balance point for my house I know it is below 7°F. We have so few hours bellow that temp to test.

Barry’s advice is perfect if you have a HP from 1990 or a newer builder’s grade unit. Some modern HP operate well down to -20°F (hyper heat the refrigerant is compressed twice sort of). My system has a 10-12 degree rise when operating at its lowest speed and it runs on low most of the time. On high speed I see over 25 degree rise and the line temp can be over 200° I do not think I will touch it.

I think the must have HP thermostat feature is the ability to lock out the emergency heat when the outdoor temp is above the balance point of your house.

Geothermal systems can have the highest COP / efficiency but if you are paying to have the loop installed I have yet to see any math that would shows a net savings before the equipment is long past its expected life with or without a tax credit.

If you are shopping for a new unit and want cold weather performance you need a few features not found in the low cost units.

1 Variable speed compressor.

2 Two electronic expansion valves.

3 Variable speed indoor fan motor.

4 Matching indoor and outdoor units with factory thermostat that communicate with the other parts of the system. By communicating I am not talking about the old 15 wire cables modern systems use 4 wires and digital signals.

Walta