# New Hot Water Heat Pump on order



## Ponderling (Mar 1, 2013)

So not really directly frugal in the short run, and maybe not even in the long run. 

I just laid out $3100 for a new energy efficient storage hot water tank for our domestic hot water.

I presently have a naturally vented gas fired storage tank I own, but it is now 19 years old, so I got looking to proactively replace it.

Rising natural gas prices, rising GHG charges, and that had me run the numbers to look at options. I could not find anything on what the rate that GHG are to rise, but up for sure.

Going with high eff electric looks to be less than $150 more a year than my present gas consumption that goes to water heating. But it will probably be less, since more electric consumption and the distribution fee level gets cheaper. A power vented gas storage tank was going to be about $1500 to buy, and to keep the insurance company happy I would need to hire a HVAC contractor to fit it up.

The new tank will allow me to seal off the existing B vent chimney, and that elimination of stack effect should reduce the number of air changes, and that in turn will cut space heating and air conditioning operating costs. 

It will suck heat out of the basement laundry and furnace room.

I might end up making a spacer system to move the existing bubble foil that lives around the furnace plenum to sit a few inches off the plenum. Then duct that area to the inlet of the heat pump. I think that adder would give it extra heat to work with when it needs to work harder to raise the colder cold water that comes in from the water main in the winter. The basement is always warm enough in the winter - the bubble wrap on the plenum was a means to cut some of the heat on the basement level. And in the summer the heat pump will have an easier job. 

Next step, maybe in 6 months, might be a drain water heat recovery coil to be fitted in the drain from the main bath shower and feed that pre warmed water straight into the cold inlet of the tank. 

The reason this went into frugality is that I plan to do the tank swap myself over the Christmas holiday break when I have a bunch of days off of work to nibble at the new power line, new condensate measures needed, etc in advance of the tank swap day.


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## prisoner24601 (May 27, 2018)

Ponderling said:


> So not really directly frugal in the short run, and maybe not even in the long run.
> 
> I just laid out $3100 for a new energy efficient storage hot water tank for our domestic hot water.
> 
> ...


I installed this same setup with a hot water heat pump and drain water heat recovery pre-heat. Has worked very well for past 5 years. A large furnace room is ideal and will gobble up excess heat from your basement if you leave doors open.


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## Covariance (Oct 20, 2020)

@Ponderling may I ask where you are located or what type of winter, summer, spring and fall temps you encounter? And what system you're planning? For context, at the moment I am engineering a hyrbrid system that uses indirect in winter and a heat pump from spring through fall.


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## MrMatt (Dec 21, 2011)

We're getting notices about the heat pump systems, but even with discounts they're costing THOUSANDS, and honestly if I just zeroed out my natural gas usage, the payback is still over a decade.

Government needs to tax natural gas much higher for me to switch.


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## Money172375 (Jun 29, 2018)

My biggest obstacle for these units is that they draw heat from the area they are in. My basement is already quite a few degrees colder than the upstairs living area. we use the basement for recreation and sleeping quarters for guests.

These units must be amazing in warmer climates where the tank is outside in a garage.


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## Ponderling (Mar 1, 2013)

Covariance said:


> @Ponderling may I ask where you are located or what type of winter, summer, spring and fall temps you encounter? And what system you're planning? For context, at the moment I am engineering a hyrbrid system that uses indirect in winter and a heat pump from spring through fall.


I live in Mississauga, about 5km north of the moderating effect of Lake Ontario. Climactically a cold humid environment with 3580 F degree days of heating.

I need to refine things on a few spread sheets I first built in 2004 when planning improved windows, doors and basement and attic insulation upgrades to final all new latest energy upgrade plans

We are usually average hottest month in July at 22C, with warmest day ave of 28C. Coldest is Jan with average for month of -6C. Coldest is usually about -14C. 
For heating design load we are supposed to use -20C exterior, and that shows about 43k BTU/h is needed to get to 22C. Sorry for mixing so many imperial and metric units. I find you sort of have to when buying US made gear HVAC gear.
For cooling design load I use 31C exterior, and that shows about 23k BTU/h is needed to get down to 25C. 

I have a new in 2020 95% 2 stage dc fan motor high eff nat gas furnace and a 2004 dying low on banned coolant compressor a/c with an even older evap coil. Then next step for us is a new heat pump. It will be backed up by furnace in coldest, but how much to let heat pump work is a matter that depends on time of use power rates. So furnace might come on m-f but heat pump might work s-s in the winter. 

I suspect I will need to do the numbers in the excel spread sheet that the NRC provides to help in these matters to make a few scenarios and then have a prospective contractor or two price the option to final the design I will go with As in single stage, two stage, or the more pricey variable speed. As I understand it the last might be best in heat, as you can buy a bigger unit and not have it put out too much cool in summer, and then work hard in winter. In winter if one and two stage units not running I think there are parasitic heaters to keep compressor oil warm for when it is worth it to run, and that drags on HSPF rating. Not an expert yet , but dusting off a circa 87 uni design course memories. 

Use the NRC design guides: https://www.nrcan.gc.ca/sites/nrcan/files/canmetenergy/pdf/ASHP Sizing and Selection Guide (EN).pdf


The back of the house, with most windows faces almost perfectly south. In summer shaded substantially shaded by a large norway maple. Once it drops it leaves we get a lot of sun in clear days in the winter. 

Probably more than you want to know but enough to let you chew on


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## Covariance (Oct 20, 2020)

@Ponderling thank you for this detailed response!


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## Ponderling (Mar 1, 2013)

So the new heater arrived and was picked up Thursday, Had to rent a van at HD since the box noted not to ship on its side. Son and I humped its 200lbs mass down to the basement one step at a time. 

Friday I gathered the needed wiring and plumbing bits. 

Saturday I ran in the new supply wire, disconnected the water and chimney and gas connections to the old tank and drained it, and moved the new tank into position and started on the new plumbing. 

The plumbing connections are on the side of this new tank. The old tank had connections on top.
I want to protect for the option of a ducted air intake on its top, and leave room to easily pull the top air screen to clean it. So quite a bit of new copper piping acrobatics was needed.

The new tank was taller than the old tank, so the shut offs I installed 20 years ago on the old tank to hope to ease its replacement were not of use. 

So the joy of shutting off and draining the the house lines of water. The old trick of wadding some bread into a pipe leading to the existing side of a new connection to keep trace water from migrating in prior to soldering it in place worked fine. I do have a few small leaks where I was stingy with the solder in the new connections to hunt down today, Sunday. 

I ran the PVC drain line for the over temperature and pressure valve to the floor, and the heat pump PVC condensate drain line along the wall to where it can dump into the existing high efficiency furnace condensate pump. 

Now that the B vent chimney is idle and plugged, in the basement, I am considering options.
I might take the chimney apart in the attic and use the chase it provides through the first and second floors to run an inlet duct for the water heater up to the exhaust fan in the main second floor bath. It has the sole shower, and has lots of warm moist air the heat pump loves to work with. I would have to joint seal and insulate this duct well where it runs though the unheated attic space to prevent condensation problems. 

But at first blush it seems to have promise. Sort of a variation on the drain water idea, which might get implemented later too. I am waiting the seem how often the new heater runs and its noise before I commit to this option. 

Last night we hopped over to my office to shower. I should have hot water back in the house using the new unit today, Sunday.


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## Ponderling (Mar 1, 2013)

So the new water heater unit runs fine. 
Hang the laundry on racks in the area of this unit and they dry overnight.
So no need to run the clothes dryer with this new water heater unless you are in a rush for something out of the washer. 

I ordered and have half installed ( the drain side so far) a 48" Power Pipe DWHR unit.
It recovers almost half the heat energy in the hot water going down the drain.
Connecting it to warm up water that goes into the cold side the water heater so the heat pump does not have such a wide temperature delta to work against to heat the water. 

I will get this in for under $800, and figure a pay back of under 5 years with our current water use being heavy on showering. 

I waited until my every second week garbage day pickup came around. 
When it did I humped the old water heater tank to the curb.
It was picked up by the scrap metal scroungers in less than an hour. 
It was too big to fit easily into my car to take it to the scrap yard myself. Oh well.


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## Ponderling (Mar 1, 2013)

DWHR unit is now in service. On my son's first shower using it I measured that the cold water going in from the on street supply line was 11.6C, and after scavenging heat from drain water left the unit at 27.6C and is piped to the input of the water heater. The second shower monitoring showed a peak temperature output of 30.3C. 

The water heater is set to heat to 65C in off peak times, so now the heat pump does not have to work as long to get to its set point on showering, which is by far our largest use of hot water.


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