Electricity Savings With A Heat Pump Water Heater

I am eager to share proof of projected 40% electricity savings, in replacement of an ordinary resistance electric water heater, with a beautiful heat pump water heater, HPWH. The installation was reported in post an exemplary heat pump water heater.

 

I have the unusual resource of a chart going back 22 years. This chart through December 2021  includes a full year since the water heater replacement. Savings are very evident, seeming to be the expected 40%:

From 2012 to 2018, there was remarkably little need of electricity, me living alone. Demand might have been met with a modest photovoltaic array but for neighboring trees to South, and adverse West facing of the major roof surface. For the past four years, occupancy and electricity demand have doubled, with two wonderful renters in this 1955 home now fully weatherized and modern, radon-free. It is a rare rental opportunity, managed with some originality. All utility costs are auto-paid by me. The renters pay a fixed total of $200 per month for electricity, natural gas, water/ sewer and trash/ recycling, balanced annually against actual payments. Where I see the costs and share pain, I am moved to do all possible to reduce costs; thus the HPWH.

I believe charts showing control of somewhat-voluntary expenses, can be rewarding and inspiring. And, yes, they can be dispiriting if not achieved. We wonder why monthly utility bills include charts such as this of the October 2021 electricity bill:

There are many variables of weather, behavior and occupancy, in monthly bars. Why a December spike? Visitors? October comparisons pre- and post-HPWH 278 kwh vs 390 kwh, a drop of 29%, is as expected, but probably under-states actual savings accumulated. Is that really 40%, as hoped?  Sometimes the trends in this bar charting, are concrete.

From my Excel file:

See annual savings of about : ($680 - $460.)  $220, a 32% reduction of annual total dollars. With $220 per year savings, $18 per month on average, the material total cost of $577 (plus my free labor) is repaid in fhree years. If the water heater serves twenty years, the present value of the annual savings, applying my Perpetuity Math, is $24,000. What a good deal!

In January 2022, find the deal quite diminished for a new investor. My $399 purchase in November 2020 was of: Rheem Professional Prestige ProTerra Hybrid Electric Water Heater PROPH65 T2 RH375-SO

https://www.rheem.com/product/professional-prestige-proterra-hybrid-electric-water-heater-proph65-t2-rh375-so

Offered today at homedepot,com, $1199 after $500 discount:

https://www.homedepot.com/p/Rheem-Performance-Platinum-50-Gal-10-Year-Hybrid-High-Efficiency-Smart-Tank-Electric-Water-Heater-XE50T10H45U0/312742081

 Local distributor General Pacific offers this unit is $1658 minus $500 = $1158, not a compellingly better deal. Equivalent models from Rheem and from AO Smith, cost the same,

Energy Trust of Oregon in its public web site doesn't bother to promote the heat pump water heaters it subsidizes with public funds, while subsidizing flimsy LED light bulbs with far less savings potential, I think the HPWH promotion is very muddled and.is probably not working, The better bargain two years ago was a missed opportunity too, I suppose. We should be moving these by hundreds of thousands, involving DIY home owners as well as contractor allies of Energy Trust..Maybe slow motion is a factor in ballooning  cost.

Failed promotion of heat pump water heaters is a big disappointment to me as an advocate of affordable rental living (my house as exemplary). I am so happy for what I have done. Who else even thinks of this?

Here post updates of the monthly electricity usage tracking, ever more clearly the dramatic savings with the HPWH. Hot water is much more nearly "free", not proportional to the number of house residents, perhaps more free than with some rooftop solar collector, that would be badly oriented, shaded by a neighboring tall Douglas Fir. 

For a house that could "go solar", a heat pump water heater must be key in being solar-ready.

Local-Option Energy Codes are not the best or only tool for meeting municipal carbon goals through residential energy conservation.

 I found this message in news feed 6/9/2021, from group Onward Oregon:

Tell your legislators to support 100% clean energy and stronger local energy efficiency standards

A message from our friends at Climate Solutions:

House Bills 2021 and 2398 are concrete steps we can take to reduce air pollution, address the climate crisis, and help protect our state's beauty and livability for decades to come.

 

Please urge your state legislators to prioritize climate action by passing House Bills 2021 and 2398 this year!

Bill; 2398 action touted at the  link is mainly the adoption of Reach Code, 

Relating to building codes; declaring an emergency.

Adds Reach Code to state building code as specialty code and gives power of administration and interpretation of Reach Code to Director of Department of Consumer and Business Services. Requires director of Department of Consumer and Business Services] to follow same process in adopting or amending Reach Code that director follows in developing residential and commercial building codes and to ensure that statewide Reach Code mandates achievement of not more than 90 percent of site energy use that other statewide residential and commercial building codes require. Requires director to adopt Reach Code not later than October 31, 2021, and at same time director adopts corresponding residential specialty code or corresponding structural specialty code, updating Reach Code at least every three years. Permits municipality to adopt Reach Code and require adherence to code as minimum construction standard and method within municipality's jurisdiction notwithstanding requirement that state building code be uniform and applicable to all municipalities in state. Provides that municipality's adoption of Reach Code is not amendment to state building code and does not require approval of director. Provides that municipality that does not adopt Reach Code does not need to enforce Reach Code within municipality's jurisdiction. Declares emergency, effective July 1, 2021.

Learn about Reach Code at the following links:

https://www.oregon.gov/bcd/codes-stand/Pages/reach.aspx

https://www.oregon.gov/bcd/codes-stand/code-adoption/Documents/21reach-res-draft.pdf

Good heat pump water heaters are further supported. There is modest improvement of exterior wall insulation, with 2x4 framing allowed. There is no change of attic insulation required.

Where my interest is in the achievable improvement of existing homes, I am disappointed in this push upon me to support legislation. Building codes apply only to new homes prior to first occupancy. And, yet, outdated and interfering Plumbing Codes are addressed in municipal permitting of the HPWH opportunity. We must not let permitting delay, or even halt, energy conservation.

I believe this is feel-good action to do something for residential energy conservation, to be credited to municipal goals in carbon reduction, via easy change of building codes.A simple "Reach Code" is the largest break from statewide codes that might get past opposition. The goal isn't really-better building code. It is the allowance at all, of local options.

Local option is not limited to code adoption. Much more can be achieved toward municipal goals by actually directly inspiring prospective new-home owners, and especially, existing-home owners through financing benefits that might be offered with burgeoning public-bank deposits of the revenue of existing  accepted, carbon taxes. In Oregon, these taxes include mainly our Public Purpose fund take of 3% on residential and commercial energy consumption in the form of electricity and natural gas. In City of Portland, largest corporation profits are now subject to a 1% carbon tax on profits. All of this existing carbon tax is spent-down every year with little benefit to consumers and to green jobs workers in clean energy.

My wishful thinking upon proper use of carbon tax revenue as funding of beneficial  loans-only from perpetual and growing funds. is addressed here:

Good Things: Oregon Carbon Taxes and an Oregon State Bank

Improvements in my thinking are overdue.  They might grow through beginning at last, of legislative action. The first needed action is a constitutional amendment to undo a still-in-effect absurd badly-spelled 1880 Oregon Constitution prohibition upon a State Bank.

Article X!, Section 1. Prohibition of state banks.

The Legislative Assembly shall not have the

power to establish, or incorporate any bank

or banking company, or monied [sic] institution

whatever; nor shall any bank company,

or instition [sic] exist in the State, with the

privilege of making, issuing, or putting in

circulation, any bill, check, certificate,

prommisory [sic] note, or other paper, or the

paper of any bank company, or person, to

circulate as money. —

Note: The semicolon appearing in the signed Constitution

after the word “whatever” in section 1 was not

in the original draft reported to and adopted by the

convention and is not part of the Constitution. State v.

H.S. & L.A., 8 Or. 396, 401 (1880).

The public surely supports repeal of this prohibition. Let's get that done.

Success: Passive Control of Radon in My Single-Family House

My House lies along the path of Missoula Floods erosion of land about 110,000 years ago, in a dramatic stage of erosion that formed The Columbia River Gorge,

https://en.wikipedia.org/wiki/Ice_Age_Floods_National_Geologic_Trail#/media/File:Wpdms_nasa_topo_missoula_floods.jpg

Concentrated glacial deposits are associated  with higher concentration of radon release from soil.

The Oregon Health Authority warns of high radon levels in homes of East Portland:

https://geo.maps.arcgis.com/apps/MapSeries/index.html?appid=f7691be8bc40430fa8480fc325287f7c

For too many years of my life, I was aware of radon levels persistently above ten picocuries per liter in my home. EPA recommends: Fix your home if your radon level is 4 picocuries per liter (pCi/L) or higher.

A Citizen's Guide to Radon - US EPA

I have at last achieved the needed fix, by novel means employing the natural drive of chimney effect. I think this is a really big deal. By my example, every home could be fixed with modest up-front cost and without any operating cost or degraded home value by zip  code or neighborhood. This must be good news, not bad, for all of us, including abatement contractors. 

(11/12/2012)

My quest for passive control of radon began with fitting two 4" warm air pipes sealed full-length, between my crawl space and my attic. There is excess space in a bathroom wet wall; put some of that to use. There will be significant chimney-effect drive of air flow when the pipe(s) are completed through-roof.

I expected to make this work someday, avoiding a radon pump if possible. How big is the needed pipe? Maybe 6" diameter?  The two 4" pipes equal one 6" pipe, and that much fits in the wall. If one is enough, the other might serve as an ample  wiring conduit between crawl space and attic. 

Minimize wet wall thickness above a tiled shelf. With an epoxied-on copper band, avoid reliance on caulk in sealing the new tub behind backer board and tile. Read more about the tub install in this blog post of October 2013: Insulate Exterior Wall of a Bathtub or Shower

For years then, the pipes did nothing, not connected through-roof and not collecting from the soil of the crawl space. House radon levels were unchanged.

(August 2019)

Dig this trench in the dry, hard dirt of my crawl space.

Hereafter I will own an over-abundance of these tubs. I disposed this many tubs of dirt, a carload, twice.

Use landscape cloth to separate collection ducting from the dirt.

The gravel fill is crushed quarter-minus.

At both bottom and top of 4" ducting, engage 4" warm air pipes with a spun-aluminum roof penetration adapter. In the crawl space the adapter flat face is upward. A wide circle of two-sided butyl tape bonds the adapter to the Americover Goldentouch 16 mm scrim-reinforced plastic sheeting, the central element of my conditioned crawlspace. On the roof, the adapter makes a better water barrier under an additional layer of shingles. A roof cap just blocks rainfall.

Here is another use of rope-form putty weatherstripping.

There has been a large binge of benefit from the clean ground cover for plumbing, wiring and heating of the grand kitchen remodel off in the far distance at left here. 

At last, it makes sense to complete the roof penetration  of the radon ducting.

Here are several months of observations by the renters of my house. Please see this report and other album pages that support and go beyond, the content of this blog post:

Passive Radon Control, My House

Stack-effect drive is proven to be ample in summertime conditions with a path having very small flow resistence.. At engineeringtoolbox.com, find a calculator of natural draft, working whenever the outside temperature is less than temperature in the radon-suction stack, as occurring most of the time, through all seasons. In the calculator try a 6 meter closed-column height, and a temperature difference of 40 °C (-20 to +20°C)... Result: 0.4" wc.

A typical Fantech fan at noisy maximum power not-wanted, delivers 0.9" wc.

It is easy to see that natural drive should work

(April, 2021)

Work near the radon vent to add some ceiling LED lights in the living room.See that extensive flooring is an asset to ceiling access, not an obstacle.

an exemplary heat pump water heater installation

Here is my new heat pump water heater installation, for assessment by the reader. I have responded to new demands, exceeding those of the cheap electric heater now recycled. It is taller. Water pipes to the tank are longer, yet are simpler and more secure. Thoughtful cradles at last support against tip-over in an earthquake roll. Behind the drywall, at both sides of this room corner, house shape is stabilized by 1x8 shiplap sloped 45°; now benefitting the tank seismic support. I know where the wall joists are, from nail locations on interior drywall. At the cradle assemblies, the larger pieces of 3/4" plywood are set with long screws finding wall joists if I am lucky. Rely actually upon 1 5/8" deck screws engaging shiplap, strong for lateral loads, to carry seismic loads from the cradle assemblies.  The cradle assemblies adjusted to best tank position, are bonded to the bigger plywood pieces and to the shiplap directly, with 2" deck screws.

A new, simple, dedicated plumbing drain, serves the pumped drip of a condensing gas furnace, as well as the flood of HPWH condensate. Users, the wonderful renters of my home, have informed choices to readily make upon hot water temperature and economy of mode. They will be pleased by more than 50% savings of energy for hot water, amounting to more than $20 per month. I am pleased to have achieved this prideful conservation at material cost of just $577, where the well-rebated $1200 heater cost just $399.

Learn more in this job photo album. See that I have followed manufacturer instruction that tank water lines not atop the tank, so distant from wall connections, should be flexible PEX. PEX couplings at the tank are wrench-detachable without need of oddly-prescribed little metal garden hoses having dangerous quickly-releasable face seals.  The tank is tied to cradles well-anchored upon diagonal shiplap behind the drywall. Condensate is directed to a dedicated plumbing drain. 

Here are the Rheem graphics of expected installation. My installation is superior in having the Cold shutoff very accessible with an inherent heat trap within the wall; isn't that true? I don't understand the thermodynamics of this.

Google the title of this post, to see if residential HPWH installation standards exist.

Find these videos:

A 2014 installation by This Old House has odd, simpler HPWH installation of an unidentified unit where tank piping is at the top.

How to Install a Heat Pump Water Heater | This Old House

Federal resources of Bonneville Power Administration are offered through Hot Water Solutions, an initiative of NEEA, Northwest Energy Efficiency Alliance.

How To Install a Heat Pump Water Heater: Professional Version

How To Install a Heat Pump Water Heater: Consumer Version

See that side-mounted water connections are a common innovation with heat pump water heaters, Manufacturers should align against destructive plumbing code that demands tank connection with at least 18", not more than 24" flexible metal hoses. Could anyone defend need of that? Every added connection adds cost and failure risk.  Please find marked-up Plumbing Code for State of Oregon. I find fault too, with seismic requirements. Big steel straps have no value without intelligent anchors. If slack permits a heavy tank to roll with momentum, straps are doomed.

At 2/27/2021 add reference to installation of a SANDEN CO2 found in this Matt Risinger YouTube video. Choose an outdoor unit if you can, for the better efficiency and quiet.

Start viewing at 12:00.

Find an overview of heat pump water heaters, by Matt Risinger, Top 5 Heat Pump Water Heaters, July 2020.