Many people are installing a mini split in their RV nowadays. They are very happy with the performance of the mini split. So, I decided to post a guide for anyone who is thinking of installing a mini split in their RV.
Installing a mini split in an RV is different from a residential home. There are a few important things to take note of when selecting and installing a mini split in your RV.
Mini Split Selection for RVers
A mini split has one indoor unit and one outdoor unit. Both units are connected by two refrigerant pipes (liquid & gas), one set single phase power cable (live-neutral-earth) and an extra signal cable for the inverter model.
Mini splits have two models; a) cooling only model and b) cooling and heating model. Most of the time, cooling only models are named “air conditioner” while cooling and heating models are named “heat pumps”.
Typically, mini splits are available at 9000 BTU, 12000 BTU, 18000 BTU and 24000 BTU. Some mini splits go up to 30000 BTU and 36000 BTU.
Most mini splits sold today are equipped with inverter technology that enables them to regulate capacity based on the cooling/heating load requirement. Hence, they don’t cycle on and off like the RV rooftop air conditioner.
A conventional RV rooftop air conditioner turns either on or off (100% or 0% capacity). On the other hand, a 9000 BTU inverter mini split can operate anywhere between 4400 BTU and 10500 BTU. They start off with a full capacity and gradually ramp down to maintain the room temperature.
Inverter mini splits will never shut off but maintain running at a certain capacity. With inverter technology, the room temperature is precisely controlled and thus, you feel more comfortable and it is more energy-efficient this way. See more from my post about why mini splits run all the time and how it helps efficiency.
Mini splits come with two voltage models; a) 110-120V model and b) 220-230V model. Most mini splits offer 110-120V for 9000 BTU and 12000 BTU models only while 220-230V is available for all capacities.
For an RV, you would want to use a 110-120V model as it is the most practical voltage. A 220-230V will limit you from staying in 30A parks. Furthermore, a 110-120V model is more suitable for solar power.
See my post Most Efficient Mini Splits: Cooling, Heating & Different Types to find out the top 115V mini splits with the highest efficiency.
Because the insulation of RVs is not as good as standard homes, you can’t use online BTU calculators to determine the cooling/heating capacity needed. Most of them resulted in a capacity of about 20 BTU per square foot which is most likely not enough for an RV.
Instead, use 40 BTU per square foot. Most RVs are about 300 square feet. Hence, you are most likely to end up with a 12000 BTU mini split. If you hardly visit the south, you may use a 9000 BTU mini split.
If you have a large RV, it may be around 350 square feet which you’ll need about 14000 BTU. However, a 12000 BTU mini split will still do. It’s just that it’ll take a few minutes longer to cool/heat.
Nevertheless, if you are hanging around in places where the summer temperature goes as high as 100°F, you may want to get two 9000 BTU mini splits because an 18000 BTU mini split usually requires 220-230V power unless you are fine with it.
Never use an oversized mini split because it won’t be able to reduce the humidity level to a standard comfortable level at around 55% relative humidity. On a side note, mold and fungus start to grow at 65% relative humidity and above.
Mini Split Price
Typically, a budget 12000 BTU mini split (110-120V model) costs about $750-$850 to purchase. However, mini splits from big brands are usually cost more than $1000. Again, we’re talking about the 110-120V model because the price of 220-230V mini splits is slightly different.
Most people choose to install by themselves but if you need a professional to help, you may have to pay around $300-$1500 depending on your location.
The mini split comes with the indoor bracket included. However, you are most likely need to do some modification works in order to mount both the indoor unit and the outdoor unit.
The cost of the modification work is difficult to have even a ballpark figure but a standard mini split outdoor unit wall bracket cost around $50 to purchase which you need to buy it separately if needed.
Other stuff such as refrigerant lines and drain hoses are included when you purchase a mini split. If you’re doing it for a standard home, you’ll only need basic tools and a 3.5″ hole saw cutter.
However, some people buy additional flexible refrigerant pipes for the outdoor unit joints to prevent the solid copper pipe joints from cracking and leaking refrigerant. An alternative solution is to leave a few extra inches of copper pipe at the joints so that it has some buffer length to move around.
A typical 12000 BTU mini split (110-120V model) starts with about 1000W of power usage. It gradually reduces to about 500-800W depending on how much cooling/heating is needed. Current is around 4-7A most of the time.
As for a 9000 BTU mini split, the top wattage is about 800W and it may hover around 400-600W depending on the cooling/heating load requirement. Current is around 3.5-5.5A most of the time.
Mini split manufacturers usually have a recommended breaker size in their specification sheet which you can refer to when needed. I strongly suggest you read it because mini splits draw more amps when there is more load and the outdoor temperature is very high/low.
On a side note, most mini splits are using AC power. Some people call a mini split as “DC air conditioner” which is quite misleading if you ask me. Read my post to understand why people are calling inverter air conditioners as DC air conditioners.
Most mini splits are capable of working up/down to an ambient temperature of 5°F (-15°C) for heating and 115°F (46°C) for cooling.
Beyond that, they have a safety device that may act to stop the operation of either the indoor and outdoor unit or just the outdoor unit to protect the system from damage.
Mini splits are designed to cool the room temperature down to about 75°F (24°C) and bring the indoor air humidity level down to about 55% relative humidity. Check out my post on the dehumidification of mini splits and the dry mode that everybody is talking about.
However, oversized mini splits are not able to dehumidify properly which can cause mold to grow at above 65% relative humidity.
Mini Split Controller
All mini splits are controlled by a remote controller. Manual control is possible at the indoor unit in case a reset is needed or the remote controller is lost but depending on the brand and model.
The remote controller can also be used to determine error codes which allow you to identify the root cause and do the repair work. Also, it is powered by standard batteries.
Mini splits have many modes and functions which you can activate it using a remote controller. Read more about it from my post on all of the mini split air conditioner modes where I explained each of their purpose and usage.
Energy Efficiency Rating
Mini split is a high-energy-efficient air conditioning system. According to Energy Star, mini splits use 60% less energy for heating and 30% less energy for cooling when compared to other room air conditioners.
While most mini splits have a standard energy rating of around 20 SEER, some premium models have an energy efficiency rating as high as 26 SEER.
Seasonal energy efficiency ratio (SEER) is the measurement of the cooling output versus the input power of an air conditioner. The higher the ratio, the better the efficiency and thus, the lower the power consumption.
See my post Most Efficient Mini Splits: Cooling, Heating & Different Types to find out which mini splits have the highest SEER rating.
A typical 12000 BTU mini split weighs around 20 lbs for the indoor unit and about 60-70 lbs for the outdoor unit depending on brand and model. The bigger the capacity, the heavier the mini split.
A standard mini split creates about 20-25 dB of noise at the indoor unit and around 45-50 dB of noise at the outdoor unit. Some mini splits are noisier but all of them are generally considered as very quiet.
Inside an RV with the mini split run at low fan speed, you can whisper to each other. When a mini split runs at high fan speed, you still can have a normal conversation without having to yell at all.
As for the outdoor unit, when it starts to run, it is quite noisy if you are near. After about 15 minutes, it will ramp down and so, the noise will be reduced significantly. You will have no problem sleeping near the outdoor unit.
In addition, having a mini split outdoor unit outside your RV mostly won’t disturb the people in other RVs in the park.
Mini splits come with a pre-charged refrigerant. Most mini splits sold today are using R-410A refrigerant and this kind of refrigerant is harmless to humans but inhaling concentrated R-410A refrigerant is fatal.
The R-410A refrigerant is stored inside the outdoor unit. After you’ve done installing it, open the refrigerant ports using an Allen key to release the refrigerant to the copper line and the indoor unit.
On a side note, if you ever have a leak, the R-410A cannot be charged in without first vacuum out all of the remaining R-410A refrigerants because the R-410A is made of a mixture and the ratio must be correct in order for the mini split to work properly.
Mini Split Placement in RVs
It is very challenging to install a mini split in an RV, especially for smaller RVs. Big RVs usually have no problem finding a spot for the mini split indoor unit, but installing the outdoor unit may be challenging too.
Nevertheless, there are two important things to make sure you get right during the installation; a) space above the indoor unit and b) space behind the outdoor unit. Both are the space for return airflow.
While mini splits in standard homes have good space clearance accounted for easy maintenance, RVs don’t have the luxury space. Thus, maintenance is difficult but possible.
For RVs, the mini split indoor unit should have at least 2″ of space clearance at the top. For the outdoor unit, it should have at least 2″ of space clearance at the back.
These are the minimum requirement for most mini splits to ensure there is space for return airflow so that the mini split will not trip. Obviously, if you have more space, give more clearance to improve the performance. Read more about mini splits placement from my post.
Following I’ll show you an example of a mini split place in a fifth wheel RV.
Above illustration, I scaled the virtual mini split as close to the real size as I can for a more realistic demonstration. Anyway, there are quite a few people who have done installing a mini split in their RVs. Here is a table of resources:
|RV Type||Information||Link to YouTube Video|
|Travel Trailer||General placement and electrical work||T&N Services LCC|
|Camper||Cabinet modification for the indoor unit||RV Living Yet|
|Class C||Mini split basics and completed work||Gone Boondocking|
|Class A||Extensive modification for the outdoor unit||Sky Management|
|Fifth Wheel||DIY installation & modification||I Bought a RV|
A mini split is a great alternative heating and cooling solution for RVs with little to no noise compared to the built-in air conditioner. Many RVers are getting a mini split to replace the noisy RV air conditioner.
Mini splits are an excellent air conditioner. They are widely used in homes and buildings around the world.
However, installing a mini split in an RV is very challenging. A lot of modification work is needed. However, there are many resources out there which you can refer and follow.
Here, I’ve covered the basics of mini splits and the selection guide specifically for RVs. In most cases, a 110-120V 12000 BTU mini split is the best for an RV.
For a reliable mini split, I recommend getting the Daikin 19 series.
If you need me to help with your HVAC system, purchase the Email Consultation service.
This article was originally published on aircondlounge.com. Actions will be taken for unauthorised republication of this article.
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