Hybrid Hot Water Heater Saves 69 Percent On Energy Consumption
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:author: Russell Ballestrini
:slug: hybrid-hot-water-heater-saves-69-percent-on-energy-consumption
:date: 2019-02-05 09:28
:tags: Solar, Project
:status: published

*Disclosure: This post contains affiliate links.* See `full disclosure page here </disclosures-and-terms/>`_.

Exactly one year ago I fufilled a `longtime childhood dream </fulfilling-childhood-dreams-solar/>`_ when I invested in roof top solar on my house in Eastern Connecticut (Zone 6b).

Over the past 12 months, I have religiously tracked my families energy consumption using both a "`Kill A Watt <https://www.amazon.com/gp/product/B00009MDBU/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=B00009MDBU&linkCode=as2&tag=russellball0b-20&linkId=b3410667dcccb96e343e7cda77ff46ff>`_" and a `Curb <https://www.amazon.com/gp/product/B015IY0Z3E/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=B015IY0Z3E&linkCode=as2&tag=russellball0b-20 &linkId=727da547a2b0a22fa53016191c2cf313>`_.

Along the way, I have found my largest energy consumer (abuser).

Heating water.

My traditional electric water heater had a monthly operating cost of $85. Worst yet, during some winter months, 100% of my solar production was soaked up by heating water!

I demanded a better way!

... and I found one ...


Hybrid Electric Hot Water Heat Pump
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.. image:: /uploads/2019/ao-smith-hybrid-hot-water-heater.jpg
   :alt: AO Smith Hybrid Hot Water Heater
   :align: right
   :width: 300

My new unit (`A.O. Smith 50 Gallon Voltex Hybrid Electric Heat Pump <https://www.amazon.com/gp/product/B079RCGK12/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=B079RCGK12&linkCode=as2&tag=russellball0b-20&linkId=7590d68023bc0d6b244587826aea587e>`_) transfers ambient heat from the air into water.

The technology is relatively old, basically an air conditioner or refrigerator run in reverse.
Instead of dumping the cold into the tank, it dumps hot and as a by-product produces cold air.

Yes that's right, this unit will suppliment my summer cooling because it will dump cold air while it produces hot water. The heat pump also serves as a dehumidifier, so I no longer run one of those!

The install was mostly identical to a normal water heater, however there are a couple extra requirements:

* The unit needs at least 400 square feet to pull ambient air
* The unit produces condensate, similar to a dehumidifier or air conditioner, which needs to drain somewhere.

Additionally the heat pump fan produces a bit of sound, not terrible, and seems quiet to me.

If you have a traditional electric water heater, you meet the extra requirements, and you consider yourself an environmentalist, you need to get a hybrid water heater.


Finances
==============

These units currently run between $1200 - $1500 but I'll break down the complete finances of my project.

.. code-block:: text

 + $1,149 purchase price
 +    $65 delivery
 +   $100 pipes and fittings
 -   $300 instant rebate
 -   $200 mail-in rebate
 -   $200 craigslist 3 year old unit
 ===================================
 +   $614 


I replaced the unit myself, with help from my father-in-law. I don't own a truck, so I decided to have it delivered for $65. I bought $100 worth of pipe and fittings, mostly because I don't want to learn how to sweat copper, so I use `sharkbite fittings <https://www.amazon.com/gp/product/B01AS48PBS/ref=as_li_qf_asin_il_tl?ie=UTF8&tag=russellball0b-20&creative=9325&linkCode=as2&creativeASIN=B01AS48PBS&linkId=81ade3de2fc030c163112c53c7049885>`_ which cost more but are fast and simple to use.

My state offers an instant $300 in store rebate, plus a $200 mail in rebate.

The old unit was only 3 years old (came with the new house purchase) so I sold it on craigslist for $200 (MSRP was $899).


Return on investment
=======================

Ok, so $614 to replace a working unit, am I crazy? What is the expected ROI?

Well, I've only had the unit for a month, however my energy consumption for heating hot water went from $85/mo to $30/mo. 

Let's just round down to $50/mo savings.

Ok so in 12 months the unit will pay for itself. Even without the rebates you're still looking at only a 2 year ROI before the unit starts paying dividends.

That's not all.

I don't need to run a separate dehumidifier in my basement because the new unit removes humidity as a by-product!

... but wait there's more!

This unit also produces cold air as a by-product which means free supplimental cooling during the summer!

A water heater, dehumidifier, and air conditioner all-in-one!


What is the catch?
===========================

.. image:: /uploads/2019/curb-ao-smith-hybrid-hot-water-heater-usage.png
   :alt: Curb Realtime Energy Consumption of AO Smith Hybrid Hot Water Heater
   :align: right

There is no catch, but you do have to agree on a small trade off, hot water recovery time.

Instead of using 4,500 watts for 45 minutes (.75 hours), a hybrid hot water heat pump uses 350 watts for 3 hours.

Trading the slightly longer hot water recovery times, gives you:

* a significant reduction on your energy bill
* dehumidification
* supplimental air conditioning / cooling


.. code-block:: text

 # traditional.
 4500 * .75 # == 3375 watts or 3.375 kWhr to recover
 
 # hybrid heatpump.
 350 * 3 # == 1050 watts or 1.050 kWhr to recover

The decrease in consumption means a huge savings of 69%!!!

.. code-block:: text

 # percentage decrease.
 (3375 - 1050) / 3375 # == 69% !!!

So what are you waiting for? Honestly, if you are thinking about going solar, you should tackle this project first, right now!


.. contents::
