Ever thought how the refrigerators, air conditioners and room heaters in your home operate? Or ever relished a heated swimming pool? In the case of heating without the use of a combustable like propane or fuel, a heat pump is to be thanked. Heat pumps are machines that essentially pull out heat from the air and supply it to where it is needed. Likewise, they are also used to cool the surroundings by releasing heat into the air, which is a mechanism very similar to an air conditioner.
How does an AC heat pump work?
A heat pump is simply an electrical device that transfers heat from a place where it is not needed to another place where it is needed. There are varieties of heat pumps, but all of them operate on a single basic principle of heat transfer. Polar opposite to what a layman thinks of electrical devices in his home, heat pumps transfer heat from one place to another instead of creating the same leading to greater energy efficiency. Kind of like a “backwards air conditioner.”
Heat, in its natural state, tends to flow downhill. Therefore, it gravitates from a locus with high temperatures to a locus with low temperatures. That’s where heat pumps step in.
A heat pump makes use of a small amount of energy to reverse the natural tendency of heat. In other words, a heat pump pulls out heat from an area with low temperatures to make it available in an area with high temperatures, much against the natural flow of heat.
Take the example of a refrigerator.
It’s an insulated box at its core with a heat pump installed inside. An evaporator coil is placed in this insulated box predominantly in the freezer compartment. A heat pump absorbs heat from the freezer and transfers it to the outside environment mostly from beneath the point where the condenser coil is located.
However, heat pumps work best in moderate climates.
What are the advantages of heat pumps?
One of the major benefits of a heat pump is that they maximize energy efficiency by simply transferring energy from one place to another. They do not generate energy on its own.
The following listicle will provide you an insight with regard to the advantages of heat pumps.
- Running costs are low – Heat pumps are energy efficient and therefore are cheaper to operate than systems which operate based on combustion. If a system is highly energy efficient, it can help in long-term savings on energy. Even though the ground source heat pumps can be priced up to 20,000 pounds, this energy saving investment can induce savings up to 1400 pounds every year.
- A minimal amount of maintenance required – Again when compared with the combustion heating systems, a heat pump requires relatively less maintenance. Specific facets of the heat pump need to be checked once a year, a task that can be performed by you as well. However, it needs to be checked by a professional installer once every three or five years.
- Safety of Operations – Heat pumps ensure greater safety of operations as compared to combustion-based heating systems. There isn’t an open flame, or an burning of heating materials.
- Reduction in carbon emissions – Unlike combustion-based systems, heat pumps have an efficient conversion rate of energy to heat, thereby reducing the magnitude of harmful carbon emissions into the atmosphere. Water source heat pumps have energy efficiencies as high as 600 percent.
- Facilitate cooling of air by process reversal – Heat pumps push heat to move from locations with low temperatures to locations with high temperatures, against the natural movement of heat. This process reversal enables the efficient cooling of surroundings during summers.
- Last Longer – Due to less energy consumption, heat pumps last relatively longer than combustion systems. A well-maintained heat pump can last for as long as 50 years, the average life-span revolving somewhere around 14 to 15 years. They are constant providers of heat during the phase.
- Assistance for installation readily available – The government runs an RHI scheme under which 2 programs aid the installation of heat pumps. For homeowners, social and private landlords, and self-builders, payment under the Domestic Renewable Heat Incentive (RHI) scheme is the recommended option. Likewise, Non-Domestic Heat Incentive is an option available to public sector businesses, industries and organizations.
What are the Disadvantages of a Heat Pump?
Heat pumps are not all fairy tales when it comes to its operations. There are a number of negative aspects to it. Those are listed below.
- Upfront costs hit the roof – Though heat pumps survive longer thereby reducing operating costs in the long span of time, the first time investment or the upfront costs per se is purchasing these electrical devices is pretty much higher than other RV accessories.
- Installation can be problematic – Installing heat pumps turns out to be a far difficult affair than what is made to believe. Replacing an air condition with one is easy. But installing one on a camper for the first time? Difficult.
- Not everything is biodegradable – Some of the fluids used by heat pumps are not eco-friendly and raise serious environmental concerns. That makes the sustainability of heat pumps for heat transfer objectionable. It is recommended, however, to use biodegradable fluids.
- A significant investment of time and efforts required – Installation of heat pumps takes time and effort and equally disrupts the usual workflow of your time better spent in the hammock.
- Operate best only in moderate temperatures – Heat pumps are difficult to operate in too low or too high temperatures. Trying to operate a heat pump in freezing cold areas may ultimately damage the system because the required level of heat efficiency is not achieved.
- Heavy reliance on electricity to operate – Heat pumps cannot be full-fledged carbon-neutral electrical devices because they rely on electricity to a large extent. However, since they are electrical devices, they can be teamed up with solar applications like solar panels to achieve a zero net carbon level.
- Special planning permissions required in some places (Residential Units) – In places like Wales and Northern Ireland, special planning permissions are required while in places like Scotland and England, permission depends on the place where you reside and the size of your property.
How to install a heat pump?
Before we jump on to the step-by-step process of heat pump installation, let us first get equipped with the tools that are required for installation. They are:
- Wire stripper
- Cable tie
- Tape and scale
- Hole saw
All right, let’s get on with how to actually install a new heat pump into an RV.
Step 1. Prepare the roof
If you have a rooftop heat pump, make sure the RV roof can hold up to 130 lbs of weight. Make a 14 ¼” x 14 ¼” square on the roof using a measuring tape and a scale. Cut the square and frame the opening to support the heat pump. The frame should be at least ¾” thick and made of wood for better insulation. Keep an entrance hole for the wires, power supply, and communication cables.
Take the condenser out of its box and place it outside your RV. It helps to convert heat and transfer it into your camper.
Step 2. Sizing the air distribution duct system
The duct material you use must meet RVIA Standard requirements according to the year of manufacture of the RV. Insulate all discharge air ducts to prevent condensation. Make sure you seal the duct joints properly. Filter the return air openings and keep at least 40 sq in the area around it free of any obstruction. (this is for new installs not replacing existing air conditioning systems.)
Step 3. Route a copper wire
Route a 120 VAC supply wire, grounded copper wire in front of the box you cut in your roof. The wire should be at least 15” long for easy connection to the junction box. It should comply with the National Electrical Code ANSI/NFPA-70 and CSA Standard C22.1.
Route another dedicated 12 VDC supply wire from the converter or battery of the RV to the roof opening. Connect the three conductor cable with the thermostat after passing it through the roof opening. Both wires need to be 15” long and stick at least 6” from the thermostat mounting location. If your system has a gas furnace, you will have to route two 18 gauge thermostat wires towards the roof opening.
Step 4. Install the thermostat
Always install the thermostat close to a partition but away from doors, windows, and the next wall. Never expose it to direct sunlight or heat. Take it out of the box and separate the thermostat’s base. Insert the three conductor cable that you routed previously through the back assembly. Cut the outer wire by 3” and shield it with a ¼” insulator.
Mount the thermostat on the wall and connect red/white wire to the 12V+ terminal, orange wire to the COMMS terminal, and black wire to the 12V– terminal. Do not touch the terminals until you make sure all the connections are tight. Push the wires into the back and fix the thermostat cover.
Step 5. Install the rooftop system
Place the system in the frame you made according to the instructions mentioned in the installation manual. It is different for every brand. Make sure you don’t slide the unit across your roof and damage it.
Have someone stand under opening for proper placement. Pull down the system electrical cord and mount the junction box. Install the connector and pull the remaining wires into the RV. Screw the return air cover and ceiling template from inside the RV on the rooftop. Use double-sided tape to stick the insulator on either side of the unit.
Step 6. Make final connections
Connect the previously routed +12 VDC supply wire to the unit return air opening red wire. Connect the –12 VDC supply wire to the black wire of the opening and one of the three wire cable of the thermostat. Connect the gas furnace wire with the blue wire of the opening unit.
Now you have to connect the red and orange wire to the remaining two of the three wire cable. Make the 120 VAC power supply connection
Step 7. Taking care of the decorative parts
Take off the return air grill and place the return air cover over the ceiling template. Install the template and reinstall filter return air grill over the air cover. Screw it tightly, and your work is done. Switch on the unit and check if it is working properly.
The installation can take you anywhere between one hour to three hours. The more help you have, the faster you will be done. Keep all screws ready according to the steps for your convenience. If you get it installed by a professional, the installation can cost you anywhere between $200 and $1,000.
Be sure to check out this breakdown of Heat Pumps for your RV that shows you what to look out for when selecting one.