OLMO OW-P08HS115WF Review: 8,000 BTU 115V Wall AC and Heater
A small heat and cool wall unit with 8,000 BTU/h cooling and 4200 BTU/h heating that runs on a standard 115V outlet and has a built-in smart kit for app and voice control.
By Daniel Brooks
Updated October 22, 2026
The OLMO OW-P08HS115WF is one of the few heat and cool wall units that runs on a standard 115 volt outlet. It delivers 8,000 BTU/h of cooling and 4200 BTU/h of heating, uses R-32 refrigerant, and has a built-in smart kit for phone and voice control. OLMO lists 52 dB, and the unit has a 4.2 out of 5 average from 12 ratings in our through-the-wall air conditioners with heat category.
Our Verdict
For a bedroom, home office or studio where the sleeve has only a normal outlet, this OLMO is a practical way to get cooling in summer and a little warmth on cool mornings, with app control on top. It is also one of the more affordable heat models we cover. You can run it from the push button panel with its LED display, the included remote or your phone.
Keep expectations realistic for the heater. At 4200 BTU/h, it takes the chill off a small room rather than heating it through a cold spell, which is typical for 115 volt heat units. The sleeve is sold separately, and the listing does not give a room size.
OLMO 8,000 BTU Through-the-Wall AC & Heater
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Key Specifications
| Feature | Specification |
|---|---|
| Brand | OLMO |
| Model | OW-P08HS115WF |
| Type | Smart through-the-wall air conditioner with heat |
| Cooling Capacity | 8,000 BTU/h |
| Heating Capacity | 4200 BTU/h |
| Power | 115V, 1 phase, 60Hz |
| Efficiency | 9.6 (listed) |
| Refrigerant | R-32 |
| Noise Level | 52 dB (listed) |
| Controls | Push button panel with LED display, remote, smartphone app, voice |
| Dimensions | 24.21 x 14.53 x 20.28 inches (W x H x D) |
| Weight | 77 pounds |
| Wall Sleeve | Sold separately |
| Warranty | 1 year limited |
Cooling Capacity and Room Size
OLMO lists 8,000 BTU/h of cooling but no square footage. In the ENERGY STAR chart below, the 8,000 BTU row covers rooms of about 300 to 350 square feet, so the unit suits a standard bedroom, a nursery, a guest room or a small office. OLMO also lists apartments, condos, garages and studios as suitable spaces.
ENERGY STAR publishes this general guide for sizing a room air conditioner by floor area:
| Room Size (sq ft) | Cooling Capacity (BTU/hr) |
|---|---|
| 100 to 150 | 5,000 |
| 150 to 250 | 6,000 |
| 250 to 300 | 7,000 |
| 300 to 350 | 8,000 |
| 350 to 400 | 9,000 |
| 400 to 450 | 10,000 |
| 450 to 550 | 12,000 |
| 550 to 700 | 14,000 |
| 700 to 1,000 | 18,000 |
Adjust for your room: reduce capacity by 10 percent for a heavily shaded room, increase it by 10 percent for a very sunny room, add 600 BTU for each regular occupant beyond two, and add 4,000 BTU if the unit cools a kitchen. Source: ENERGY STAR.
Heating on a Standard Outlet
The heater produces 4200 BTU/h. That is modest, and it is limited by what a standard 115 volt outlet can supply. It is enough to warm a small bedroom on a cool spring or fall morning, a home office before work, or a guest room that the main heating does not reach well. It is not enough to heat a room through a cold winter, and it is not meant to replace central heat.
The big advantage is convenience. Most wall units with stronger heaters need a dedicated high-voltage receptacle. If your sleeve has only a normal outlet, a 115 volt heat model like this one is the way to add any heat at all without electrical work.
Smart Control
The built-in smart kit lets you control the unit from a compatible smartphone, and the listing names voice control as well. You can switch modes, change the temperature and schedule cooling or heating from anywhere. That is particularly handy for heat: start the unit from bed on a cold morning and step out into a warmer room.
Power and Installation
The unit is designed for 115V, single phase, 60Hz and uses R-32 refrigerant. OLMO asks buyers to confirm the receptacle before ordering, which here is a standard household outlet. The chassis measures 24.21 inches wide, 14.53 inches tall and 20.28 inches deep and weighs 77 pounds. The sleeve is not included and must be bought separately. OLMO sells its own sleeve, and a sleeve-included version of this unit is also available.
Noise and Efficiency
OLMO lists 52 dB, which is low for a wall unit and makes the OW-P08HS115WF a good bedroom candidate. The listed efficiency figure of 9.6 is typical for a small heat and cool unit.
Tips for Heat Mode
Aim the louvers downward when heating, since warm air rises and otherwise collects near the ceiling. Close the door to the room so the small heater is not trying to warm a whole apartment. A schedule that starts heat half an hour before you wake up makes the most of its output, and on very cold days, pair it with the building’s main heat rather than relying on it alone.
Comparing 115V Heat Models
Several brands now offer 8,000 BTU wall units with heat on a standard outlet, and most list a similar heater output. The differences come down to extras. This OLMO stands out for its built-in smart kit and low listed sound level. Others offer longer warranties, sleeves in the box or more owner feedback. If smart control and quiet operation matter most, the OLMO is a strong pick. If you want a sleeve included, OLMO sells a version of this unit with one, which costs more but saves a separate purchase.
Who It Suits Best
The OW-P08HS115WF suits bedrooms, nurseries, offices and studios with a standard outlet at the sleeve, especially for smart home users who want cooling in summer and a little warmth on cool days. It is less suited to larger rooms, cold climates that need real heating capacity, or buyers who want a published room size.
Pros and Cons
| Pros | Cons |
|---|---|
| Heat and cool on a standard 115V outlet | Modest 4200 BTU/h heater |
| Built-in smart kit, app and voice | No published room size |
| 52 dB listed sound level | Sleeve sold separately |
| R-32 refrigerant | Heavy for its size at 77 pounds |
| Affordable for a heat model | 1 year limited warranty |
Who Should Buy It
| Who Should Buy It? | Who Should Look Elsewhere? |
|---|---|
| Bedrooms and small offices | Large living rooms |
| Homes with only standard outlets | Cold climates needing real heat |
| Smart home users | Buyers who want full specs |
| Rooms that run cool in spring and fall | Anyone without a sleeve |
For more choices, see our picks for the best 115V through-the-wall air conditioners with heat and the best smart through-the-wall air conditioners with heat.
Final Verdict
The OLMO OW-P08HS115WF brings cooling, light heating and smart control to a small room without needing a high-voltage outlet. Its heater is modest, but for shoulder seasons and cool mornings it is a convenient, quiet and affordable all-in-one wall unit. You can check the current price and details for the OLMO 8,000 BTU Through-the-Wall AC & Heater.
Frequently Asked Questions
How much heat does the OLMO OW-P08HS115WF produce?
OLMO lists 4200 BTU/h of heating capacity.
Does it need a special outlet?
No. It is designed for 115V, single phase, 60Hz.
Does it have Wi-Fi?
Yes. A built-in smart kit supports smartphone and voice control.
Is the sleeve included?
No. The wall sleeve is sold separately.
About the author
Daniel Brooks is a home cooling editor at WikiCooling, covering window, portable, through-the-wall and mini-split air conditioners, fans, and dehumidifiers. He researches cooling capacity, energy efficiency, noise levels, installation requirements, and buyer feedback to help homeowners choose the right unit for their room size, climate, and budget.