Tiny House Heating, Ventilation, and Air Conditioning

Marc Bilodeau/ Planning, Smart Sensors, Tiny House

In Maine, there was a very long cold spell between Christmas through the first week and a half of January. The temperatures (in Fahrenheit) were in the single digits during the day and negative numbers at night. That doesn’t include the windchill. However, something happened during this cold spell that made me rethink my tiny house heating plan.

What Happened?

My recreational room has an HVAC split system and baseboard heating. I keep the baseboard heating off since I have a split system to manage the temperature. Around the new year, the room above my garage was cooler than normal. That’s not unusual since the weather was very cold outside. The next day the room was 28F (-2C), and my split system was blowing cold air. I thought it odd, so I turned it off since I don’t use the room except to run on my treadmill.

Unfortunately, I thought the baseboard pipes were drained when the split system was installed. Sadly, I was wrong. They had water in them. Therefore, the baseboard heating pipes burst in two places. Water dripped through the floor and into the garage. Thankfully, the issue was quickly resolved with the help of a plumber. Now, the baseboard heating is doing a great job keeping the room comfortable. The spilt system is off since it’s not necessary right now.

Why didn’t the split system keep up? Heat pumps use the outside air to help generate heat. This can be done even with temperatures near or below freezing. They work well in moderate temperatures. However, when temperatures drop below freezing, they begin to lose efficiency. At some point, they can’t do the job and simply blow cold air. In most systems, this is around 5F (-15C). Therefore, a secondary source of heat is needed to properly heat a home. As a result, I question the reliability of a split system to heat the tiny house.

Other Observations

Since there currently is no heating system in the tiny house, the primary source of heat is a portable garage propane heater. Although this isn’t a permanent heating solution, it does a great job maintaining the temperature.

tiny house heated by propane heater

Propane heating is nice and commonly used in tiny houses. However, propane does release moisture in the air. Moisture can be damaging over time, and will require either a dehumidifier or an HVAC system capable of controlling humidity.

My personal opinion is propane heaters like the dickinson marine propane fireplace are a good solution. Although, reviews are mixed.

Ventilation is not a Problem

There are several options to provide fresh air into a tiny house besides the LUNOS e2. Since June 2017, the LUNOS e2 System continues to pass fresh air through the tiny house. Overall, I love my LUNOS. There is noticeable difference in air quality when it’s on. Therefore, I’ll continue to sing its praise and appreciate its effectiveness.

Rethinking Tiny House Heating and Air Conditioning

At the moment, there is a Pioneer 12000 BTU Mini Split sitting in the garage ready to install. However, I’m considering a different solution since The Great Pipe Burst Incident of 2018.

Tiny House Heating and Air Conditioning

Although I did some research on HVAC for tiny houses, I did not realize that when the outside temperature drops below operating levels that it simply blows cold air.

The Envi Heater Experiment

I’ve been aware of the Envi Heater for some time. However, I want a single system for heating and cooling. So, I didn’t really consider this unit. Of course, rethinking mean trying new things. Regardless, a secondary source of heat is highly recommended with a split system.

Tiny House Heating - The Envi Heater Experiment
Testing if the Envi Heater can maintain temperature

The advantage of this heater is it only needs 475W of power. That is amazing considering the average desk space heater uses about 1000W. The split system I have uses 1600W – 1700W at full power. Hence, the Envi Heater has its advantages when used with an off-grid solar system. In this case, that’s less than a third of the power.

For this experiment, I’ve installed a temporary temperature sensor in the tiny house. I tracked the inside temperature, outside temperature, and the overall power consumption for a week. After the Arctic Blast, there were a few warm days around 50F (10C). However during this experiment, temperatures returned to normal. On the first day, the temperature dropped from 50F to 14F (10C to -10C).

The Results

For context, everything was powered off except for the Envi Heater, the ceiling fan, and a temperature sensor. No one was in the tiny house during the time the data was collected. The walls have nothing on them. There are no blinds or shades on any of the windows.

tiny house envi heater data
trending indoor and outdoor temperatures

Unfortunately, the data shows the Envi Heater cannot be the primary source of heat during the winter where I live. However, my data suggests that the Envi Heater may be a good solution for those in slightly warmer environments where temperatures in the winter average a bit higher. I’m confident that three seasons out of the year the Envi Heater would work great for me.

Wood Stove

I love a good campfire. So part of me wants a wood stove. The heat is dry and warm, and watching the flames is peaceful and enjoyable. That being said, there are a few options available for tiny house stoves. My personal choice would be the Kimberly Wood Stove.

The benefits of a wood stove is it requires no electricity or propane. It’s very off-grid friendly. Fuel is available all around. One simply needs to pick up some twigs and small logs for hours of warmth. Maintenance is minimal such as routinely cleaning the chimney and emptying any excess ash.

The downside is that it can be messy, and it takes time to start and stop the heat. It requires monitoring and hands-on to maintain and control the temperature. Additionally, gathering and storing wood for long periods of cold weather requires space. Most people don’t have the luxury to store a cord of wood even if they’re just twigs and small branches.

No matter the cons, a wood stove is a great option to heat a tiny house. Several tiny house owners can be found on YouTube talking about their tiny house wood stoves and how much they love them.

Good Heating Options, but what about Cooling?

According to historical temperatures, Maine is warm and pleasant in the summer. The average highs are in the low 80F (28C) and the average lows are in the upper 50F (15C). However, heat waves and humidity are very common. Temperatures can easily get into the 90F (32C), and on some days near 100F (38C). Crazy indeed!

Other than central air, the typical options are either an air conditioning unit in the window, or a portable unit that pipes the air out a window. The portable unit is bulky and takes up a lot of space. On the other hand, the window unit tucks nicely into a window and requires little space. Although, both solutions will adequately cool a tiny house.

Tiny House HVAC options
The left can both heat and cool, while the right is a room size window air condition unit.

There are also clever low power and inexpensive solutions. The internet has all sort of ideas, like this one. If putting together new fangled contraptions is your thing, then creativity may win the day!

Conclusion

There are many different options to heat and cool a tiny house. The internet is a wonderful resource to read blogs and watch videos of opinions and experiences before making a final decision.

Although a recent disaster made me rethink the initial plan, a second round of homework proves that a split system is still the best option for this tiny house. It provides both heat and cooling that accommodates almost all range of temperatures in my area. Also, it requires a small amount of wall space. However, it is important to have a secondary source of heat. For that, the Envi Heater will be my back up source of heat to help the split system in those especially cold days.