Installing Residential Heating and Cooling Technology in an Era of Energy Price Inflation
by Ryan M. Ferris
Ryan Ferris is a resident of the Columbia neighborhood in Bellingham.
Its official! The natural gas crisis is in full swing. After five years of warning from pundits as diverse as Alan Greenspan to Matthew Simmons, American consumers now face steep and accelerating natural gas pricing. Theres a very good chance that your total cost per therm under the coming MDU/CNG1 merger will be near $1.75/therm in the near-term future. What is the appropriate residential response to increased heating costs?
My wife and I decided to completely re-architect our home ventilation, cooling and heating. Although, the ultimate cost for such a long-term project was admittedly expensive, the accrued benefits are important. Among these benefits are increased quiet, reduced energy usage, cleaner air, more well distributed heating and cooling and improved health and sleep. Our solution also facilitated a shift from a natural gas furnace to a heat pump as a heating/cooling source. Importantly, this shift will enable us to use photovoltaic power generation and Washingtons net metering laws as a future heating/cooling energy source.
The old home we bought in 2003 was just a bit of a heating/cooling relic. The method used to heat the home previously (an airtight wood stove) wasnt appropriate for someone who suffers from chronic respiratory distress. The old aluminum pane windows and sliding doors, while state of the art at some point in the past, are considered serious heat sinks today. The uninsulated or poorly insulated walls, the old doors, the narrow heating registers, the poorly ventilated basement, soffits, attics and cracked siding were problems I have been solving one step at a time.
Performance Tuning Homes Thermal Envelope
Sometimes I feel like I will be performance tuning our homes thermal envelope for the rest of my life. Not exactly my idea of relaxing weekend fun! But in any event, we have called in contractors (one at a time) for the big improvements: whole house insulation, 12 new windows, two new sliders, painting and sealing, new bathroom fans, and our energy status signature purchase: a Ken Marr whole house HVAC (Heating Ventilation Air Conditioning) remodel that included installation of:
Rinnai tankless water heater
Carrier Infinity 96 percent efficient furnace
Honeywell Air Filtration System
Carrier Infinity 16 Heat Pump
All new heating ducts and register replacement
The installation was difficult and time-consuming for Kens team because of tight basement and heating closet conditions, but they really created a finished product of beauty and great use. In designing our system, Ken paid attention to my comments about air quality and reduced power consumption. He made it a point to include an ample return, manually adjustable fresh air intake, and at our request, replace all our ducting in our tight crawl space. Because of my respiratory difficulties and mold/pollen allergies, clean air is a real priority for me. He also explained technology to me as if I was a partner in the outcome. This approach won over a geek like me pretty quickly.
Carrier products has reputedly invested $250 million in research and development recently for their heat pump line. It shows. Our heat pump has proven to be a somewhat miraculous device. It seamlessly extracts cold air from the hot air and the converse as needed. It also removes humidity from our home enabling my wife and I to live in a comfort range of 68 72 degrees, 50 percent humidity, filtered clean air, 24 hours per day. This decreases my respiratory difficulties to a bare minimum, and makes it comfortable to work, sleep and play in our home for my wife, daughter and me.
Heat Pump Technology Benefits From Recent Developments
How does it work? Heat pump technology is quite old but has benefited from recent developments in motor efficiency and silencing, circuit board design, improved refrigerant technology, etc. An air source heat pump uses refrigerant to transfer energy. Since cooling/heating refrigerant is more efficient at this than air, water or other heat transfer mediums, a heat pump can cool or heat your house cheaper than natural gas provided it has a suitable heat/cooling source such as the ground or air.
Heat pumps function most effortlessly between 60 and 80 degrees, although they will extract the heat from cold air right down to freezing and indeed kept us quite cool when the outside temperatures were in the low 90s this July in Bellingham. To facilitate this thermal extraction, our heat pump (Carriers Infinity 16) uses a large but fairly quiet two stage compressor and fan driven by a 220V 50A circuit.
The refrigerant is cooled/heated to the desired temperature and then pumped into the coils underneath our downdraft furnace. The furnace fan distributes the heat or cold to the heating ducts/registers and the air returns for reuse, mixing with clean air and passing through a dual stage electrostatic Honeywell air filter first. Depending on the system configuration, hybrid heat kicks in at lower temperatures. This means the gas furnace begins to heat your home.
Your cost savings as a homeowner comes from using a cheaper source of energy than natural gas to heat. In fact, for late summer and early fall cold nights, the heat pump and coil is all your home may need. During the winters of a mild climate like Bellingham, many daytime temperatures are high enough for the heat pump to extract significant amounts of warmth. For those not so mild winter days and nights, our 96 percent efficient Carrier gas furnace will take over.
January in Bellingham, as most of us know, is the true test of how well we have insulated and sealed our homes and how efficient our heat sources function. This test is coming for all of us soon, amidst soaring natural gas prices and a petition for decoupling of utility rates by CNG. Decoupling legislation is a prerequisite for the completion of the MDU merger/purchase of CNG.2
In subfreezing cold, heat pumps are still more expensive than natural gas heating. However, given where the price of natural gas is going, it is entirely possible that we will take advantage of our heat pumps low ambient temperature mode, which could heat our home down to 0 degrees. I am certainly using low ambient temperature mode for these late summer/early fall nights. In practice, I have set a heat pump lockout temp at less than 45 degrees and the furnace lockout temp at greater than 55. These settings prevent the heat pump from running under 45 degrees OAT (Outside Air Temperature) and the furnace from running at more than 55 degrees OAT. For now, this represents my best guess at when the heat pump will be cheaper to heat with than gas, but Im still experimenting. Combined with the Rinnai tankless water heater, our 1,700 hundred square foot home with 600 square feet attached garage is experiencing a summer usage of about 12 therms per month or less than 1/2 of a therm per day.
For cooling during the summer, a heat pump functions like an air conditioner with some exceptions. The Carrier system allows the user to increase fresh air intake on those cool days to naturally cool your home. The mechanism for adjusting fresh air distribution is zoning technology. Zoning technology is really quite remarkable. A small motor with thermostat wires is placed on the stem trunk of the ducting. A motorized vent controls heat/cool flow as needed/directed.
For example, our office/server room is a separate zone. Ken Marrs technicians Wayne and Pavel installed an eight-inch duct to our office/server room to shift much needed air there. I keep our office warmer than the rest of the house essentially because the heat generation of our PC servers is very high and the large duct keeps me cool enough. In another zoning example, our family room is sometimes closed off in the winter; its separated from the rest of the house by exterior grade French doors. This zone does not always have to be heated to the same temperature as the rest of the house. Zoning allows individual airflow control as well. I notice sometimes at night that I often want the airflow to the main living rooms and family rooms kept on low continuously, but the bedrooms on auto.
Is a Heat Pump Cost-Effective?
Has the heat pump saved us money? Its too early to tell, but August 2005 and August 2006 energy usage look to be almost identical. PSE provides you with near daily updates on your total electrical usage through their use of smart meters, so monitoring is always a few clicks away. Its a shame CNG does not have the same Web interface for their smart meters, despite having invested many millions in installing them.
In thinking why a centrally cooled house may be no more costly than a house cooled with fans and open windows, I have concluded from general observation that our thermostatically controlled devices (e.g. old refrigerator, PC servers) ran their cooling mechanisms (e.g. fans, compressors, refrigerants) much more aggressively while they were warmer.
Fans, as most of you know, do nothing to decrease heat but make humans more comfortable by increasing skin evaporation. Unfortunately, the cooling mechanisms in your 4U Intel server care little about how much you sweat. But then again, Carrier heat pumps and furnaces/blowers are very efficient, so it could just be that central air by heat pump is cheaper than the five large house fans I had previously used, in vain, to keep our house bearable during the summer.
Some of you may be wondering about such expenditures and how we financed them. For example, are their cheaper methods of achieving the same goals? How could you afford this? Keep in mind several concepts regarding the justification of the expenditures:
1. This year, nearly 10 percent of our project cost will be paid back through vendor credits and IRS rebates. This is result of the mammoth and complicated energy bill drafted by Congress and passed by President Bush last year. Personally, I dont know how long these tax and vendor credits will be available next year.
2. Matthew Simmons, the worlds top oil and gas investment banker, has produced some terribly dramatic rhetoric about the coming natural gas crisis. The drama of Mr. Simmons rhetoric, coming from such a corporate source, convinced us to act decisively now. I would prefer not to suffer energy shock or surprise when shortages of natural gas and $200/barrel oil create chaos in the existing social order. Please see: http://www.simmonsco-intl.com/research.aspx?Type=msspeeches.
Despite this, the completion of this project was not cheap and the pick-up carpentry projects related to the HVAC remodel often cost me hours of time. Substantial remodeling of any type is not for the faint of heart. However, I am a much happier camper now that I dont have to run whole house fans, adjust windows open and closed at nights and mornings, and work in an office that used to reach 84 degrees during the summer months. The health and welfare benefits justify much of the cost. However, what will really make a heat pump cost effective will be our next project: a large size installation of photovoltaic cells.
Washingtons net metering laws allow a homeowner to credit summer sunshine for winter warmth. For example, with a large enough solar array, I can get credit for excess home summer energy production that I will use in the winter, but thats a story for another article. In summary, you can do many things to decrease your need for energy, but you cant yet make natural gas on your rooftop. Thanks to improving heat pump technology, I probably wont have much need to try.
The author would like to acknowledge some of the local companies and other building suppliers that have helped us with our energy and other remodeling. Other local companies not listed have simply given us good advice and their time:
Chucks Clean Crawls (Burlington)
Evans Glass (Seattle)
Radiant Barriers from http://www.radiant-barrier.com
Panasonic Whisper Quiet Bathroom Fans sold at http://www.energyfederation.org
Solar Attic Fans §
1 MDU Resources Group, Inc., (NYSE: MDU) is a multi-dimensional enterprise comprised of regulated and non-regulated businesses operating in domestic and international locations. CNG or Cascade Natural Gas is Whatcom Countys current gas provider. Cascade Natural Gas serves 235,000 customers in 93 communities 65 of which are in Washington and 28 in Oregon. The merger was announced July 9.
2 According to CNG: The Conservation Alliance Plan decouples recovery of the cost of providing service from the volume of natural gas that customers use. Under Cascades current rate structure, cost recovery and profitability are tied to the volume of natural gas that customers use, creating a disincentive to promote conservation.