The tech costs more than conventional options upfront, but federal tax credits, new 120V models and strong savings have made them more appealing than ever.
A furnace puts BTUs into the house. A heat pump furnace pulls BTUs from the atmosphere and pushes them into the house; a gas furnace extracts BTUs from fuel and puts them into the house. An electric furnace extracts BTUs from electrical energy, and puts them into the house.
The heat pump water heater pulls BTUs from the house and pushes them into the water. They use internal air as their heat source. They do not draw heat from the outside atmosphere; they draw heat from the furnace-heated air inside the house.
The two systems are not “separate” or “independent”. The heat pump water heater is daisy chained to the furnace. Both use the same, household air for opposite purposes: one sinks heat into the house, the other sources heat from the house.
And how is it a bad thing that it is making good use of the heat around the furnace to heat up water? You do realize that the electricity in the heat pump also is making some heat on its own.
All that energy can be harvested for a hot shower or bath instead of having a heat pump outside in the colder temps running at a lower efficiency. On top of that, the furnace will not always be running throughout the year, and the warmer months will be more beneficial to have the heat pump than a gas water heater.
I am assuming that the heat pump water tank and gas furnace are in the basement, or garage. not inside the well insulated house…
On top of that, the hot air is directed out of the gas furnace to the house, while the air surrounding the gas furnace is lost heat that can be scavenged by the heat pump. They are independent and work for separate reasons.
I am assuming that the heat pump water tank and gas furnace are in the basement, or garage. not inside the well insulated house…
Ah. That’s the issue. Your assumption is faulty.
Water heaters have water lines leading to them. Anywhere the temperature regularly falls below freezing, the water heater must be located inside the heated structure, not exposed to the elements. Otherwise, the plumbing could freeze. The basement may be colder than the rest of the house, but it is still part of the heated structure.
If your basement, garage, or whatever room contains your water heater is not within the heated structure, you are living well south of Ohio.
The Washington State Building Code Council voted to update the state energy code to require all-electric water heating in new multifamily and commercial buildings.
Until recently, all of my installations had been in basements here in upstate New York. There are several obvious advantages to locating a heat pump water heater in a basement.
It’s definitely not something the south states are alone in installing water heated tanks in basements or the garage.
Where sub-zero temperatures are regularly experienced, you cannot install a water heater or other plumbing in an unheated space. The cold water supply lines will freeze and burst.
It’s rare for northern homes to have water heaters in garages. In the few cases where they are, the tank is installed in a heated alcove or closet within that garage.
-20F winter nights and exposed plumbing do not mix.
Washington basements are heated.
New York basements are heated.
Ohio basements are heated.
Do you understand this now? Do you understand that northern water heaters need to be installed in heated spaces? Do you understand that northern basements are heated spaces?
Did you read the articles where they are talking about heat pump water heaters? There is even a mention of placing the tank on the roof. This is a dead end conversation. I am not going to argue about this as it does not help or will convince people up north how to install their water heaters. Its a moot topic and this should just die. I said my piece and you said yours. I am still convinced that having the gas furnace and heat pump combo is a good way of going about the whole setup.
With a gas furnace and a heat pump water heater, the furnace is providing the heat for the water, and all of the electricity used by the water heater during winter is wasted, relative to using a gas water heater. Gains are only made in the summer, while the water heater is helping to cool and dehumidify the home.
Your second article discussed using heat from the dryer in a second floor laundry space. The “waste” heat from the dryer would have normally gone into heating the house, reducing demand on the furnace. The author saw “waste heat” from the dryer, but didn’t think about where that “waste” heat was going, and didn’t properly account for it in his calculations.
You cannot treat a heat pump water heater as “independent” and “separate” from the home’s HVAC system unless it is actually drawing heat from outside the home.
I am not going to argue about this as it does not help or will convince people up north how to install their water heaters.
The question isn’t where they should install them. The question is whether they should switch to heat pump water heaters at all. If using gas heat, that answer is “no”, because these just shift which appliance will be burning that gas, and use additional electricity on top of that.
The same is true for an old house with resistive or radiant heat: the heat source for a heat pump water heater in a resistively-heated house is the resistive heating. The heat pump doesn’t make the household’s radiant heating any more efficient, it just adds additional load on that system.
Heat pump water heaters only make sense where with a hypothetical “split” system that draws heat from outside the home in winter, or if the household heat source is considerably more efficient than either a gas water heater or resistive electric water heater.
Common heat sources more efficient than gas or resistive electric water heaters are heat pumps, solar, geothermal, or a climate that doesn’t require much supplemental heat. If you have any of these, a heat pump water heater will make sense.
If you don’t have any of those, you have to compare the summertime gains against the wintertime losses to find the net efficiency.
The article I linked about Washington state says that new built homes have to install heat pump water heaters. This means its not a question on which to choose but how to make the heat pump water heated tanks more effeciently sound. This topic is a moot point, and should be let go.
First, That’s Washington. Not Ohio, New York State, or the overwhelming majority of the US.
Second, the Washington rule only applies to commercial buildings and large, multi-family residences: apartment buildings. It does not apply to single-family homes. I can’t find the specific criteria, but I doubt it applies to duplexes or triplexes.
Third, the rule only applies to new construction, and not renovation. You can still replace existing gas water heaters with new gas water heaters, you just can’t install a gas water heater in a new, large building.
Fourth, that same rule in Washington requires heat pumps for HVAC, and prohibits gas furnaces. The situation you envision of gas furnaces and heat pump hot water is prohibited in the circumstances envisioned in that rule. The only situation where we can consider gas heat and heat pump hot water is in renovating existing buildings, where the Washington rule does not apply.
Your “Washington” rule is therefore irrelevant to your argument, and my point is perfectly relevant. The conclusion is simple: you must replace a gas furnace or resistive/radiant electric heat with an HVAC heat pump before you will save energy from a heat pump water heater during winter. During winter, whatever your heat source your furnace uses will be the heat source for your hot water. If that is gas or resistive heating, your total efficiency will drop, and every watt hour consumed by your water heater will be wasted compared to a water heater that uses the same type of heating as your furnace.
A furnace puts BTUs into the house. A heat pump furnace pulls BTUs from the atmosphere and pushes them into the house; a gas furnace extracts BTUs from fuel and puts them into the house. An electric furnace extracts BTUs from electrical energy, and puts them into the house.
The heat pump water heater pulls BTUs from the house and pushes them into the water. They use internal air as their heat source. They do not draw heat from the outside atmosphere; they draw heat from the furnace-heated air inside the house.
The two systems are not “separate” or “independent”. The heat pump water heater is daisy chained to the furnace. Both use the same, household air for opposite purposes: one sinks heat into the house, the other sources heat from the house.
And how is it a bad thing that it is making good use of the heat around the furnace to heat up water? You do realize that the electricity in the heat pump also is making some heat on its own.
All that energy can be harvested for a hot shower or bath instead of having a heat pump outside in the colder temps running at a lower efficiency. On top of that, the furnace will not always be running throughout the year, and the warmer months will be more beneficial to have the heat pump than a gas water heater.
I am assuming that the heat pump water tank and gas furnace are in the basement, or garage. not inside the well insulated house…
On top of that, the hot air is directed out of the gas furnace to the house, while the air surrounding the gas furnace is lost heat that can be scavenged by the heat pump. They are independent and work for separate reasons.
Ah. That’s the issue. Your assumption is faulty.
Water heaters have water lines leading to them. Anywhere the temperature regularly falls below freezing, the water heater must be located inside the heated structure, not exposed to the elements. Otherwise, the plumbing could freeze. The basement may be colder than the rest of the house, but it is still part of the heated structure.
If your basement, garage, or whatever room contains your water heater is not within the heated structure, you are living well south of Ohio.
https://www.coffman.com/news/water-heating-washington-standard/
https://www.greenbuildingadvisor.com/article/where-does-the-heat-pump-water-heater-go
It’s definitely not something the south states are alone in installing water heated tanks in basements or the garage.
You’re still not comprehending.
Where sub-zero temperatures are regularly experienced, you cannot install a water heater or other plumbing in an unheated space. The cold water supply lines will freeze and burst.
It’s rare for northern homes to have water heaters in garages. In the few cases where they are, the tank is installed in a heated alcove or closet within that garage.
-20F winter nights and exposed plumbing do not mix.
Washington basements are heated. New York basements are heated. Ohio basements are heated.
Do you understand this now? Do you understand that northern water heaters need to be installed in heated spaces? Do you understand that northern basements are heated spaces?
Did you read the articles where they are talking about heat pump water heaters? There is even a mention of placing the tank on the roof. This is a dead end conversation. I am not going to argue about this as it does not help or will convince people up north how to install their water heaters. Its a moot topic and this should just die. I said my piece and you said yours. I am still convinced that having the gas furnace and heat pump combo is a good way of going about the whole setup.
With a gas furnace and a heat pump water heater, the furnace is providing the heat for the water, and all of the electricity used by the water heater during winter is wasted, relative to using a gas water heater. Gains are only made in the summer, while the water heater is helping to cool and dehumidify the home.
Your second article discussed using heat from the dryer in a second floor laundry space. The “waste” heat from the dryer would have normally gone into heating the house, reducing demand on the furnace. The author saw “waste heat” from the dryer, but didn’t think about where that “waste” heat was going, and didn’t properly account for it in his calculations.
You cannot treat a heat pump water heater as “independent” and “separate” from the home’s HVAC system unless it is actually drawing heat from outside the home.
The question isn’t where they should install them. The question is whether they should switch to heat pump water heaters at all. If using gas heat, that answer is “no”, because these just shift which appliance will be burning that gas, and use additional electricity on top of that.
The same is true for an old house with resistive or radiant heat: the heat source for a heat pump water heater in a resistively-heated house is the resistive heating. The heat pump doesn’t make the household’s radiant heating any more efficient, it just adds additional load on that system.
Heat pump water heaters only make sense where with a hypothetical “split” system that draws heat from outside the home in winter, or if the household heat source is considerably more efficient than either a gas water heater or resistive electric water heater.
Common heat sources more efficient than gas or resistive electric water heaters are heat pumps, solar, geothermal, or a climate that doesn’t require much supplemental heat. If you have any of these, a heat pump water heater will make sense.
If you don’t have any of those, you have to compare the summertime gains against the wintertime losses to find the net efficiency.
The article I linked about Washington state says that new built homes have to install heat pump water heaters. This means its not a question on which to choose but how to make the heat pump water heated tanks more effeciently sound. This topic is a moot point, and should be let go.
First, That’s Washington. Not Ohio, New York State, or the overwhelming majority of the US.
Second, the Washington rule only applies to commercial buildings and large, multi-family residences: apartment buildings. It does not apply to single-family homes. I can’t find the specific criteria, but I doubt it applies to duplexes or triplexes.
Third, the rule only applies to new construction, and not renovation. You can still replace existing gas water heaters with new gas water heaters, you just can’t install a gas water heater in a new, large building.
Fourth, that same rule in Washington requires heat pumps for HVAC, and prohibits gas furnaces. The situation you envision of gas furnaces and heat pump hot water is prohibited in the circumstances envisioned in that rule. The only situation where we can consider gas heat and heat pump hot water is in renovating existing buildings, where the Washington rule does not apply.
Your “Washington” rule is therefore irrelevant to your argument, and my point is perfectly relevant. The conclusion is simple: you must replace a gas furnace or resistive/radiant electric heat with an HVAC heat pump before you will save energy from a heat pump water heater during winter. During winter, whatever your heat source your furnace uses will be the heat source for your hot water. If that is gas or resistive heating, your total efficiency will drop, and every watt hour consumed by your water heater will be wasted compared to a water heater that uses the same type of heating as your furnace.