New Standards Proposed For Water Heaters

[launderess]

You knew this was coming...

'The draft rule would require that, in order to become more efficient, most common-size electric water heaters use heat pump technology and gas-powered heaters use condensing technology."

https://thehill.com/policy/energy-e...r-efficiency-rule-for-new-home-water-heaters/

 

[bradfordwhite]

Heat pump water heaters are a bad idea because they are expensive and complicated, not reliable, and NOISY.  So of course, lets go in that direction.

Push the junk onto people until the realize what a bad idea it is and the market can make their $$$ while the getting is good.

 

[tomturbomatic]

I do not see a down side to this. I know that if you have a home built in the mid 50s with a brick chimney and you need a new water heater the new standards here mandate that you have to replace the flue with a stainless steel, I think, flue liner which usually costs $1500+ or did a few years ago so the higher cost of the condensing water heater probably won't be too hard a hit because the condensing water heater can vent through the wall like a condensing furnace. This Polaris heater is 95% efficient. I don't know how much more efficient these can get or if they are considered to be condensing. I have a gas water heater that uses a fan forced vent and the exhaust is cool enough to be vented through CPVC pipe

https://www.hotwater.com/products/c...is-high-efficiency/gtp-150-200/100279561.html

 

[sudsmaster]

 

 

A year or two ago I retrieved a 10 year old gas water heater that a neighbor was potting out on the street for pickup, because he was selling his home and the real estate company required a new water heater. I figured the water heater had at least 20 years left so I grabbed it (with the homeowner's permission) to set aside for when my gas water heater finally expires.

 

I also have replaced the anode rod in my water heater, which probably has increased its lifespan.

 

[henene4]

Not making the gas ones condensing seems just weird.
Basically ALL heating systems - gas or oil - over here have been condensing for over a decade now. Even the small tankless gas systems common in many small city apartments.

It's not new technology, it's not expensive, and if you are going to burn a fuel, might as well use it fully.

Same goes for a heat pump water heater.

From a quick look, it appears the energy usage compared to a normal electric one is about 1/4.
Energy guides say usages around 500$ vs something like 125$ if I ain't looking at the wrong thing.

Even if it only lasts 10 years, not even considering the tax rebates for the heat pump one, that's the cost of the entire unit in savings in electricity.

Sure, if it is in a closet next to your bedroom, I see that that compressor could be annoying.

But anything a room away - yeah don't see the noise issue with that saving.

Biggest concern would be water temperature.
If you want 160F tank temps, a heat pump will struggle and get significantly less efficient.
Anything up to 130F should be fine though, but that might not be enough in your situation.

 

[gizmo]

What is a condensing gas water heater? I've never heard the term.

 

[launderess]

See: https://www.familyhandyman.com/project/choosing-a-new-water-heater/

https://www.navieninc.com/residential/tankless-water-heaters/condensing

While on subject:

 

[henene4]

Quick summary.

When most hydrocarbons - such as oil or gas - burn, part of the hydrogen in it combines with water.
Meaning combustion produces water vapour.

Because combustion is hot, that water is in the form of steam.

Steam stores OBSCENE amounts of energy.
Evaporating 1kg of water takes several tines the energy needed to heat it from freezing to boiling.

So, if you could condense the steam out of the exhaust, you could capture all that energy.
An since most heating applications require temperatures below boiling, you already have a way to condense the water.

That's why most fuels have 2 heating value and why you sometimes see efficiencies above 100% stated.

Most difficult thing is adding another heat exchanger AND making that heat exchanger resilient. The condensate is pretty corrosive.

 

[americana4]

Pushback against mandates is understandable, but I have no complaint with my 10 year old geospring HP water heater. Saves money, acts as a dehumidifier too. No louder than a refrigerator. No problem to date.
I like its flexibility. It can be used as a HP only, conventional electric only, or a couple of hibrid functions in between. Do most offer those options? I hope so. A useful one I don't have would be for the HP to function at first, up to a settable temp, then resistance take over when a higher water temp is desired. Do newer ones offer that option?

 

[jerrod_six]

A gas-condensing water heater will work as long as you can vent the appliance. If you live in a house with a sidewalk in front or a shared driveway you are not allowed to vent onto this. If you have no way to vent to the back of the house what are you supposed to do? This situation exists in some cities.

 

[henene4]

Wait, you don't have to vent normal gas water heaters?

That doesn't sound right... Even al gas dryer is vented.

And if you don't have to vent a gas water heater - which I again highly doubt - you certainly don't have to vent a condensing one either. Only difference is exhaust temp and moisture content.
If anything, the exhaust of a condensing one is cleaner since the water will bind some of the combustion products.

What you do need is a condensate drain which might or might not be a problem.

 

[combo52]

New more efficient, residential water heaters

My friends have had wonderful experiences with heat pump, water heaters the savings are considerable and they work just fine and in addition, they do help remove some moisture from basements in humid weather.

Reply number nine and 10, Hennik Jerrod is talking about not being able to vent through a side wall is assuming a regular gas water heater is still vented into a chimney going up to the roof of the house.

A lot of towns and areas need to update their codes to allow gas water, heaters dryers, etc. to be vented out the front or the side of the house that’s just an old code which doesn’t have any decent reasoning behind it. As you pointed out Hennik the exhaust coming out of a condensing gas water heater is not gonna be bothersome to anybody.

John

 

[henene4]

Condensing heating systems

Thought I'd share in this conjunction how heating systems work over here. I'm back home on holiday right now, so this is a pretty decent example I think.

Some data.
Our house is - energetically - fron the late 80s, so some thin insulation.
Rated living space is about 2600sqft, though it's actually 4 floors with about 1000sqft each.
Unheated basement, 2 full floors and a 3rd floor under the roof.

This system was installed in 2015.
It was sized at 18kW (that's about 61500 BTUs) even though it is still somewhat oversized (especially after the new tripple glazed windows will be installed next week).
Rotex is a now defunct company as the heat pump specialist Daikin bought them up for their hot water tank technology and for other supplement technologies.

It's a fully condensing oil heating system.
The hot water tank is sized at 300l or close to 80gal.

The main burner unit does both hot water production and heating for the house via a 3 way valve.

One water circuit runs through the tank and burner as heating medium.
One runs through the underfloor heating and radiators.

You program the system with time programs for both hot water and heating as well as desired room and hot water temps.
The room temp together with the outside temperature sensor set the target heating circuit temp.

Currently it is in "Summer" mode which stops heating regardless of outside temperature.
The hot water system is set at 52°C / 126F but only is set to be active once in the morning for an hour.

It was about 2 in the afternoon when I took the picture and the water was still at anywhere between 45C and 50C depending on tank location.
The mechanical thermometer reas 50C/122F in the top quarter of the tank while the NTC for the heating system almost at the bottom of the tank read 46,5C/116F.

The plastic pipe is actually both exhaust and fresh air running concentrically, so the system runs completely independent of inside air.

I started a manual one time hot water demand to cycle the burner on. A turned on burner is indicated by the wavey line symbol in the top middle of the display.
After 5min exhaust temp only peaked at 55C/133F.
That's why plastic exhaust pipes are totally fine.