June 9 2022 The push is on to decarbonize buildings and that means code changes and incentives to move toward carbon- free electric homes accomplished by using heat pumps for: 1) Clothes-drying, 2) Water-heating, and 3) Air-conditioning/heating via either “Air to Air” (Heat from outside air) or “Ground to Air” heat pumps (heat from underground) WHAT IS A “HEAT-PUMP” A Heat-pump moves heat via refrigerant pipes from one area to another. It DOES NOT CREATE heat as does as a space heater. The magic happens via high pressure pipes and low- pressure pipes and also the type of refrigerant chosen for optimum phase change from liquid to gas in both the high and low environments. WHAT IS A “Mini-Split” A mini split is a descriptive term for its “small” unit size versus a whole house central HVAC system. It is “split” into two sections, 1) the cassette unit inside and 2) the compressor/condenser unit on the outside of the building. The term “ductless” means not integrated into a central heating system, The potential to install the inside cassette unit anywhere makes it great for remodeling existing homes/apartments because no ductwork is required. But 240VAC power is required to the outside unit. Using an electric (resistive) floor heater is 100% efficient because for every watt used, we get one watt of heat out. The power companies love these because an electric heater appears as a direct short to their wires. (High current at 1200-1400 watts near the maximum of your breaker). A heat pump is 3 to 5 times more efficient than an electric resistive heater because we are grabbing heat from the other side of an insulated wall and sending it to the other side, that is, using available heat rather than creating heat. HEAT-PUMP DETAILS: A house has two different temperature environments: In winter we have a: 1) warm indoors via insulation and: 2) cold outdoors. The heat-pump works because of the physics of gas to liquid phase change. We can heat and cool gas-to-liquid in the warm environment and heat and cool the same gas-to-liquid in the cold environment. The magic is the pressure developed inside the refrigerant pipes by the compressor/condenser, and ALSO, the factory engineers decide on what refrigerant they want to use I.E. the chosen trigger temperature of the refrigerant best suited to naturally return to a liquid. There are many different refrigerants that have a wide range of phase-change temperatures. CO2 changes to liquid at minus 87f for example and R-410A (most common) changes to gas at minus 55F. We can change phase from liquid to gas in both the cold outside and warm inside environments due to what pressure the gas is under and heat or cool the house. (Think how a spray-can will get cold while holding your finger on the button) A cold winter day at -10F seems pretty warm to a -55F liquid. The Winter limiting factor: If the outside temperature were to get colder than -55 than the R-410A gas would naturally change state to liquid and the heat pump would no longer work. The liquid state will lose its heat and turn very cold when it vaporizes. We pump the heat by vaporization either throwing that heat to inside (heating mode) or to the outside (Air conditioning mode) via reversing the electric Heat-pump pressure zones. I.E. Spay the can inside the house or spay the can outside the house. Summary of Phase Change: The “heating side” is under high pressure to confine the gas phase- change at high temperatures and the “cooling side” is under low pressure to confine the gas phase- change in cold temperatures. The metal air -fins located at both the inside unit and outside unit do the physical transfer of heat/cold. ADVANTAGES: -Air-to-air Mini-Splits are much quieter than a window hanging air conditioner because all the noise making parts are outside, -Much faster cooling and heating than a window air conditioner, - -Much quieter than a central Air system, -Enables Zoned heating/cooling via their placement in thehouse, -No fire safety issues that electric floor heaters have, -No harmful gases from a furnace burning fossil fuels. -If there are enough PV solar electric panels feeding your house, the Heat-pump energy used is free. A Smart Home option: You can engage Voice control of your temperature on any system using “Sensibo Sky” for $100. It will connect to Alexa, Google, and Siri. COST Mini-Split and Ground Source: Mini-Split air-to-air heat pumps are great. Their cost is relatively low at about $1200 for a 9000 BTU unit plus the cost/labor of a 240-volt supply that can be piped from the breaker box around the outside of the house to where the outside mini-split compressor is located. “Ground” to Air heat pumps require very high Up-Front costs for drilling underground in the yard. A typical 2000 sq ft house requires three drillings at 300 feat deep costing about $18000 plus the cost of the main air handler/compressor in the house at $7000 plus labor. The average Colorado underground temp is about 53F good for both cooling and heating. RATING EFFICIENCY of Heat-pumps: SEER = Seasonal Energy Efficiency Rating, used to rate the Air-conditioning mode in the USA where 13 is poor and 42 is state of the art. HSPF = Heating Efficiency Rating - where 7 is extremely poor and 15 is state of the art. Europe only uses COP = Coefficient of Performance (Energy used vs Performance) Cheaper Mini Splits under $1000 will be older technology with SEER = 20. Any HVAC installer who recommends this, send him out of the house. State of the art efficient Mini-Splits have SEER=33 up to SEER=42. THE HOUSE QUALITY: Of course, the quality of your external wall and attic insulation is a key factor for how much heat is lost out of the house. Also the insulation affects the RUN-TIME required to keep warm or cool. Sealing up leaks in the house and getting the external walls stuffed with Dense-pack Cellulose is highly recommended as a first step. I have worked with 4 of these insulation companies and “Bestway Insulation” is the best I found (303) 469-0808.  They have a radio show on Saturday mornings: https://bestwayinsulation.com/mr-fix-it/   CAPACITY FOR THE WHOLE HOUSE: Mini-Splits come many sizes: 9000 (3/4 ton and most efficient), 12,000BTU (one ton), 18,000BTU (1.5 ton) and each one is more expensive. To heat a whole house would require three 9000BTU units, one for the main living room, one for the master bedroom, and one for the basement. If the kitchen is closed off from the main hall area, it may also require a mini split.  The basement unit is important if your basement is usually very cold because when standing in bare feet on the carpeted floor of your living room (above the basement), the cold floor will suck heat out of your feet even if sitting on the sofa. The basement concept is not to totally heat the basement but just to bring it up above ~60+.  The basement heat that rises to the basement ceiling will be noticeable especially for elder folks’ feet with shoes on. Another advantage of multiple mini-splits is that in the future if one goes bad, the other units are still running   My Carrier model 38MPRAQ09AA301 (Heating and cooling my house since Jan 2019) has an excellent SEER (cooling) rating of 42 and an HSPF (heating) of 15. It is a 9000BTU unit and will usually run-in low mode putting out a gentle ~100F at 200 watts. (Remember that a Hair Dryer uses 1200 -1500 watts for comparison).  When the outside temperature gets colder, the unit will jump to a second stage of about 700 – 800 watts putting out about 120F degrees.  If I set the remote control to max at 86 degrees, it will jump up to 1900 watts and try to put out about 150F.  It uses a 20-amp circuit breaker. Larger Mini-Splits require a 30amp breaker. Mini-splits must pull heat out of the outside air, and when the outside temperature is below zero, mine will use 800 watts and put out 110 to 120F but at minus 0 it is not able to go to the max heating at 150F and apparently the sensors tell it not to try. This is when multiple mini- splits all add together for a comfortable house.   NOISE: The inside cassette of the Mini-Split usually hangs high on a wall and is very quiet using the eco settings when running in low mode. Even in high mode it is quieter than a furnace running. There are also ceiling recessed units and floor standing units similar to under a hotel window. Outside: Note that the highly efficient “outside” compressors will change their RPM fan speed based on the load asked for from inside the house. This RPM can create a vibration that is conducted into the house through the house wood framing. So mount those outside compressors on the ground if possible or on a wall of the garage that is not near the living quarters. A compressor mounted on the roof may also conduct vibration into the room ceiling below depending on the framing.   ANOTHER ALTERNATIVE: Your old Furnace died: If you want to stay with a whole house gas Furnace with Central Air conditioning, there are Hybrid furnaces available which may cost less than multiple mini-splits. This Hybrid means that the furnace will NOT use gas to heat the house but use the outside air conditioning compressor in reverse mode (a Heat pump) to supply heat. It will not switch over to gas until the outside temperature is below 20F. I have witnessed these successfully used and still running since 2004. The compressor housing outside is very large due to the physics of physical surface-area required to exchange heat efficiently.

As utilities move to Time of Use rates that charge more in the weekday afternoons and evenings, you will have more control over your electric bills. Below are some ways you can change your lifestyle to take advantage of these rates. CHEAP COST : The cheapest energy is using NO energy. You can avoid using energy by: 1) Hang your clothes on the drying rack 2) Eat foods that don't require long oven and stove times 3) Use cold water for your laundry which will avoid re-heating the water in your hot water tank 4) Keep the refrigerator door closed 5) Keep lights off (however LED lights use very little electricity) 6) Use a laptop computer (17 watts) instead of a Desktop computer (200 watts) 7) Add insulative foam panels to the back sides of your refrigerator “freezer” (not over the refrigerator portion where heating escapes) 8) Place warning signs around the kitchen for reminders of new habits 9) Ensure front and back doors and all windows are closed 10) Open shades on the south side of the house in the winter and close the shades on the shaded side 11) Don't use any resistive heating if possible, You can turn on your oven with the door slightly open but set a timer for safety 12) Inspect and add weather stripping around front door 13) Caulk leaks around windows, 14) Add “outside” thermometers on four sides of the house to become aware when to close windows and save heat in the house 15) Use motion sensors on wall switches and a time on the bathroom fan 16) Provide training to all household occupants for new habits 17) Use light wall colors to reflect light rather than dark colors which absorb light, 18) Purchase a Kill-a-Watt meter for $25 and measure the watts used by your refrigerator (about 100 watts), TV (70 watts), computer, toaster, lamps, etc. It is fun to educate yourself. 19) Use a TV antenna and do not use an always-on Cable TV box 20) Close doors and heater ducts to rooms that are not used 21) Replace the furnace air-filters for better flow 22) Free Education = Attend You Tube webinars from CRES, attend CRES meetings. www.cres-energy.org LIST OF DELAYED ACTIONS UNTIL CHEAP RATES start: 1) Delay EV charging, 2) Delay dishwasher, 3) Delay laundry and drying, 4) Delay Hybrid hot water, 5) Delay cooking, 6) Vacuum the carpet only during cheap times (vacuums pull a lot of power) 7) Delay using a Hair-dryer (1300 – 1500 watts) MEDIUM COST: 1) Join a Community Solar Project to buy electricity from a shared solar array 2) Purchase energy monitors to learn which circuits are using the most power 3) Install Sun tunnels for natural lighting 4) Install storm windows as a second layer to your windows https://thinkalpen.com/products/winsert-introduction/ 5) Add a glass screen door to protect your main door from low temperatures 6) Replace LED lights that are 5 years old with brand new LEDs because today’s LEDs are more efficient than 5 year old LEDs due to technology advancements 7) Replace any refrigerator older than 2004 with an E-Star rated refrigerator (1/4 the watts) 8) Get an energy audit, https://hvacree.net/xcel-co/public_search.cfm 9) Have Xcel Energy service your home with new LEDs https://xehomeenergysquadco.as.me/schedule.php STEEP COST: 1) Get a Rheem Hybrid hot water tank $1200 and do NOT use the instant On-Demand hot water 2) Add roof top solar energy - both electric and hot water 3) Add PV Battery back up 4) Replace widows but insist on a LOW U value Example= U0.12 to U0.16 windows 5) Add thick insulation and dense-pack Insulation in your walls above ground and basement 6) Add heating with Hot Air panels 7) Add Automatic shades inside and outside 8) Add Heat-Pump Mini splits of high SEER >40, high HSPF =15 and a high COP Coefficient of Performance >4 to 1 energy multiplier TEST QUESTION: All of the above savings and inconveniences are not necessary if your PV system generates surplus electricity? FALSE! The rates of TOU will charge high rates during the early evening hours even when there is no sun. If you install energy storage through a battery backup system, you can draw power during the high electricity rate period.

BY: John E Avenson avenson1@hotmail.com Westminster CO. There are several options available when considering Solar PV (PhotoVoltaics) for your home: HISTORY: Starting January of 2006, Colorado began the huge state rebate program for PV which triggered low prices enabling many folks to invest in PV for the very first time. In 2021, these old systems have seen a few forms of degradation. The following happened to my house: 1) The squirrels chewed through my cables on the roof and this had to be repaired, 2) The Power Inverter failed just a few months after the warranty expired and it had to be replaced. 3) NREL came to inspect my panels as part of a study to determine the average annual degradation of Solar PV collection efficiency. Their study showed that the average yearly reduction was 0.7% of the original rating. My old Sayo panels depreciated by 0.6% per year. My old 2006 panels were only 170 watts per panel. Today I have a brand new system using 400 watt panels. SO! What do you do with the old PV system? It is still working but I had outgrown its capacity due to purchasing more modern luxuries plus I added an Electric Vehicle which requires more capacity of an additional 3 KW system to the house load. 1) CHEAPEST: Option 1: The cheapest way to get your first Solar PV system is: My PV installation company offered to remove and take away the old system and deliver it to folks who want to purchase an old used system. My old 4KW sold for $2400 and the company packed it up and delivered it to the new owner. Today, many folks are upgrading their old PV systems. Perhaps you can put in a request to several PV installation companies and reserve an old second hand system for your home. 2) MEDIUM: PV panels have greatly reduced in price since 2006. New panels have individual optimizers that allow the array to fully operate even when there is a shadow on one or a few panels caused by a roof gable or tree. A new 4K system may be only $10,000 compared to 2006 when I paid $34,000 but with a huge rebate of $21,000. Today’s panels are so cheap that you can afford to place them on the east, west, and north sides of a roof in addition to the optimum south side. 3) EXPENSIVE: This past February the snow storm put stress on the Xcel power grid and my neighborhood lost power EIGHT TIMES in two days. I ordered a BATTERY BACK-UP system in addition to my new panels. A battery backup is more complex, involving a lot of wiring at the breaker box to customize which breakers I want to prioritize and remain on when the neighborhood goes out. I choose the keep the circuit that runs the house Internet, the lights in each bathroom, the kitchen lights, refrigerator and garage lights. PS: Your Credit Union has low interest rates to finance Renewable energy upgrades. The photo above is a graph of one day events for charging with Sun and clouds: 14KW system.

Getting it off my chest: Growing up in the 1950s, I observed that society thought they had conquered Mother Nature and could build homes anywhere they wanted with fossil fuel heat used to make up for the deficiencies of poor orientation, construction methods and insulation of homes. Retail stores “magically” stayed warm despite huge glass store front windows. Since then, multiple generations of future children still believe in this “fossil fuel magic” as evidenced that the public still buys homes with large windows on the north, east and west and R13 walls that defy Mother Nature ( Earth’s rotation around the sun.) ``PeakOil” was once forecast to start running out around 2010 but fracking has extended our supply of fossil fuel for a couple more decades which gives us further “grace period” to be educated. Today, inexpensive PV solar panels provide free electricity for heating our homes and for free transportation. Solar Thermal Panels (water/liquid) also provide a source of warmth to the home. Solar Thermal Panels require pipes running from the panels on the roof, down to a hot water tank. Panels, whether on the roof, mounted on the ground or in a shared Community Solar array, mean we can consider electrifying our homes and remove any fossil fuel burning units, including gas Hot Water Heaters. A Home Energy Auditor will advise on the amount of BTU heating you need to keep warm on a zero degree day. See a List of auditors at Xcel https://hvacree.net/xcel-co/public_search_proc.cfm Itemizing winter Electrical heating From Cheap to Steep: 1) CHEAPEST: Electric base board heating and store-bought plug-in floor standing heaters are really low cost. Marketing folks go wild selling many fancy variations of the same basic electric heating coil - oil- based, reflector- based, fan- based etc. as if one is better than another. Heating coils are a one-to-one use of OHMs law. You only get 1 watt of heating for 1 watt used. 2) BETTER HEATING: A HEAT PUMP can act as both an air conditioner and a furnace. HOW? Let’s use some of those watts from example 1 to suck the heat energy out of the outside air and bring it into our home. REASON: Any air that is warmer than “Absolute Zero” (-459F or -273C) has energy to be had. In the winter, with a Condenser/compressor unit outside the house, Refrigerant fluid turns to cold gas at about minus 40F and therefore -17F is pretty warm by comparison. Minus 17 to the cold condenser can collect a lot of heat into the gas and send that heat into the home as hot fluid. These “better” units are cheap units with low efficiency ratings of 20 year old design with Seer levels of only 13 -16 and HSPF of 7 - 11. 3) BEST HEATING EFFICIENCY: Ground Source Heat pumps are the most efficient and have a direct conduction of energy from the dirt to their pipes buried up to 300 feet into the ground. But drilling the holes can cost $20,000, plus you must have room in your yard to drill. Air to Air heat pumps are cheap by comparison and sit on the ground outside of your house with a cassette hanging on the inside wall. Air to Air Heat pumps must exchange heat using many fins touching the air outside. Heat pumps are rated by “Work done per WATT USED” and are 3 to 4 times more efficient than electric baseboard or plug-in heating. RATINGS: SEER (Seasonal energy Efficiency Ratio) is mainly used to represent cooling efficiency ranging from CHEAP TO STEEP SEER 13 to SEER 42 where 42 is the best so far and a more expensive unit due to precise design. HSPF (Heating Seasonal Performance Factor) ranges from 7 to 15 where 15 is the best so far. In warmer climates a higher SEER is more important and HSPF is most important for Heating climates a. All manufactures will “still” supply cheap units and more expensive highly rated units. b. HVAC contractors will sell you the cheapest units and make off with your money in their pockets to buy a bigger Camper and boat. c. MOST HVAC contractors and sales folks (from my interview experience) are not aware of the existence of the highest rated units. IT IS THE RESPONSIBILITY OF THE HOMEOWNER to demand the high rated SEER /HSPF models. Until Homeowners are educated, the HVAC industry will keep selling their cheap units to you. 4) REFERENCES ABOUT BEST HEAT PUMPS: Consumers Reports has a summary of terminology for Heat pump rating, however it is somewhat out of date and written before the latest units were available: https://www.consumerreports.org/cro/heat-pumps/buying- guide/index.htm#:~:text=The%20minimum%20federal%20HSPF%20rating,15%20SEER%20and%20 8.5%20HSPF. CARRIER: INFINITY SERIES = SEER 42 / HSPF 15, Heating down to -17F and reduced to 75% at - 22F https://www.consumerreports.org/cro/heat-pumps/buying- guide/index.htm#:~:text=The%20minimum%20federal%20HSPF%20rating,15%20SEER%20and%20 8.5%20HSPF Mitsubishi: MSZ-FH06NA = SEER 33 / HSPF 13.5 Heating down to ?? https://www.mitsubishicomfort.com/products/indoor-units/wall-mounted-heating-and- cooling/compare/results FUJITSU: Halcyon RLS3Y XLTH Extra Low = SEER 33 / HSPF ?? Heating down to -15F https://www.fujitsugeneral.com/us/resources/pdf/support/downloads/halcyon-2020-full-line- brochure-02.pdf