Building an AC unit cover yourself costs an average of $90 to $340 in materials. A ready-made cover costs $170 to $680. The savings when building it yourself are decent, but the real advantage is a custom fit: your cover fits exactly around your unit, in your style, with proper ventilation. In this guide, you will learn which ventilation requirements apply, which materials are suitable, what the regulations are, and how to build a cover step by step that looks great without suffocating the AC.
What Does an AC Unit Cover Cost? DIY vs. Ready-Made
Cost Comparison
| DIY (materials) | Ready-made | |
|---|---|---|
| Simple wood cover (slats/screens) | $90 – $170 | $170 – $340 |
| Cover with louver panels (wood) | $135 – $225 | $280 – $510 |
| Aluminum cover | $170 – $340 | $340 – $680 |
| Composite or plastic cover | $115 – $280 | $225 – $565 |
| Green cover (climbing plants + frame) | $70 – $135 | $115 – $280 |
When Is DIY Worth It?
DIY is especially worth it when you need a specific size or when you want the cover to match your house or fence. Ready-made covers come in standard sizes that do not always fit your specific unit. Additionally, when you build it yourself, you can match the style, color, and material exactly to your yard or siding.
For a standard outdoor unit, you save $55 to $225 by building it yourself. It is also an easy project: you need an afternoon.
Ventilation Requirements: The Most Important Rule
The single most important rule for an AC unit cover: the unit must be able to draw in and expel sufficient air. A cover that blocks airflow causes the AC to work harder, consume more electricity, and break down sooner.
Minimum Clearance Around the Outdoor Unit
| Side | Minimum Clearance | Why |
|---|---|---|
| Front (exhaust side) | 20–40 inches | The unit blows hot air out here — blocking it causes recirculation |
| Back | 4–6 inches | Air intake — the unit draws air in here |
| Sides | 6–12 inches | Air circulation around the unit |
| Top | 12–20 inches | Hot air rises — air must be able to escape freely above the unit |
Ventilation in the Cover
- The cover must be at least 40–50% open — meaning 40–50% of the wall surface is air-permeable (slats with spacing, louver panels, mesh)
- The front (exhaust side) may NEVER be fully closed
- The top must be open or have a large grille
- Never use a fully enclosed box without ventilation openings
Rule of thumb: if you hold your hand in front of the cover and you can no longer feel the airflow from the unit, the cover is too closed.
Regulations and Permits
Do You Need a Permit?
In most areas, you do not need a permit for an AC unit cover, as long as the cover:
- Is not taller than 3–4 feet (backyard) or does not exceed the top of the fence line
- Is in the backyard (not facing the street)
- Is not a load-bearing structure or an addition
Is the outdoor unit on the street-facing side? Check your local zoning ordinance or HOA rules. Some municipalities and homeowner associations have requirements about the appearance of front-facing facades. A cover that matches your siding color is usually not an issue.
Noise Regulations
An AC outdoor unit produces 45–60 dB. Noise limits may apply:
- Local noise ordinances typically set limits at the property line (varies by jurisdiction)
- A cover can reduce noise by 3–5 dB if you use sound-absorbing material on the inside
- Do not place the unit directly against a neighbor’s wall
Note: A cover that is too enclosed can actually amplify noise through resonance. Make sure there is enough open area.
Materials: What Is Suitable for an AC Unit Cover?
Material Options
| Material | Outdoor Lifespan | Maintenance | Price (estimate) | Appearance |
|---|---|---|---|---|
| Pressure-treated pine | 10–15 years | Stain every 3–5 years | $1 – $2 per linear ft (slat) | Green-brown, weathers to gray |
| Cedar | 15–20 years | Oil every 3–5 years or let weather | $2 – $4 per linear ft | Warm brown, weathers beautifully |
| Hardwood (e.g., ipe) | 20–30 years | Oil every 2–3 years or let weather | $4 – $7 per linear ft | Premium look |
| Thermowood | 15–25 years | Oil every 2–3 years | $3 – $5 per linear ft | Modern, dark brown |
| Composite (WPC) | 20–30 years | Occasional cleaning | $4 – $7 per linear ft | Sleek, modern, various colors |
| Aluminum louver panel | 30+ years | None | $110 – $280 per panel | Industrial, clean |
| Plastic (PVC) screen | 20+ years | None | $55 – $170 per panel | Functional, less attractive |
Best value: Cedar or thermowood slats. Durable, beautiful appearance, and can be stained or oiled in any color.
Most maintenance-free: Composite or aluminum. More expensive upfront, but zero upkeep for years.
Avoid: Untreated pine (rots within 5 years) and MDF (not suitable for outdoor use).
Materials List: Wooden AC Unit Cover (Slats with Spacing)
For a Standard Outdoor Unit (36 x 14 x 28 inches)
| Material | Quantity | Estimated Price |
|---|---|---|
| Cedar or thermowood slats (1×2″) | 80–100 linear ft | $115 – $200 |
| Posts/uprights (3×3″, cedar) | 4 pieces, 40″ | $35 – $55 |
| Stainless steel screws (#8 x 1-5/8″) | 100 pieces | $12 – $17 |
| Stainless steel hinges (for access door) | 2 pieces | $9 – $17 |
| Ground anchors or base plates | 4 pieces | $17 – $28 |
| Exterior stain or oil | 1 quart | $14 – $23 |
| Rubber anti-vibration pad (under unit) | 1 piece | $17 – $28 |
Total material costs: $215 – $370
Tools
| Tool | Note |
|---|---|
| Cordless drill | Drilling and driving screws |
| Miter saw or circular saw | Cutting slats to length |
| Tape measure | |
| Level | |
| Speed square | |
| Pencil | |
| Sandpaper (120 grit) | Finishing |
Step-by-Step Guide: Build an AC Unit Cover in 7 Steps
Step 1: Measure the Outdoor Unit
- Measure the width, depth, and height of the outdoor unit — including connections and lines
- Determine which side is the exhaust side (usually the front with the large grille)
- Add the required clearance to each measurement: +6 inches on the sides, +6 inches at the back, +20 inches at the exhaust side, +12 inches on top
- These are the interior dimensions of your cover
Example: Unit of 36 x 14 x 28 inches (W x D x H) → cover interior: 48 x 20 x 40 inches (W x D x H), exhaust side open or with louvers
Step 2: Create a Design
- Sketch the cover with dimensions
- Decide whether the top stays open (simplest), gets a grille, or angled slats
- Plan an access door or removable panel — you need to reach the unit for maintenance and filter replacement
- Decide whether the exhaust side stays fully open or gets louver panels
Important: Your HVAC technician must be able to access the unit. Plan at least one panel that you can easily remove or open.
Step 3: Build the Frame
- Cut the 4 uprights to length (height of the cover)
- Attach the uprights to the ground with ground anchors or base plates — or sink them 12 inches into the ground if using 3×3″ wood posts
- Connect the uprights at the top with horizontal rails
- Connect the uprights halfway with horizontal rails for extra stability
- Check that the frame is level and square
Step 4: Attach the Slats
- Cut the horizontal slats to length
- Start at the bottom and work your way up
- Leave 1 inch of space between each slat — this provides sufficient ventilation (with 2″ wide slats and 1″ spacing, about 35% is open — add more spacing if needed)
- Pre-drill the slats (prevents splitting) and fasten them with stainless steel screws
- Use a spacer block of the right thickness to ensure equal spacing
The exhaust side: Leave it fully open, or use louver panels (angled slats at 45 degrees). Louver panels hide the unit but let air through. Angle the slats downward so the unit is not visible but air can flow freely.
Step 5: Build the Access Panel
- Build one side panel as a door — attach it with stainless steel hinges to an upright
- Or make a panel that you can unfasten with two wing nuts
- The door or panel must be large enough to reach the filters and service the unit
Step 6: Finishing
- Sand all slats lightly with 120-grit sandpaper
- Apply a coat of exterior stain or oil — this protects the wood and adds color
- Let dry according to the instructions on the container
- Apply a second coat if needed
Color choice: Pick a color that matches your fence, shed, or siding. Charcoal, black, and weathered gray are popular. Or let the wood weather naturally — cedar and thermowood weather to a beautiful silvery gray.
Step 7: Place the Cover
- Slide the cover over the outdoor unit or place the unit inside the cover
- Check that there is sufficient space around the unit
- Check that the airflow is not blocked — hold your hand in front of the cover and feel if air flows freely
- Anchor the cover to the ground or wall so it cannot blow over
- Place a rubber anti-vibration pad under the outdoor unit if there is not one already — this reduces vibrations and noise
Maintaining Your AC Unit Cover
An AC unit cover sits outside and needs maintenance — just like your fence or shed.
Annual Maintenance
| Task | When | How |
|---|---|---|
| Check wood for rot | Spring | Inspect all slats and uprights, replace rotten parts |
| Refresh stain or oil | Every 2–3 years (cedar/thermowood) | Sand lightly, apply new coat |
| Remove leaves and debris | Fall and spring | Sweep leaves out of the cover, spray the AC unit clean with a garden hose |
| Check ventilation openings | Spring | Make sure cobwebs, leaves, or climbing plants are not blocking openings |
| Lubricate hinges | Yearly | Apply WD-40 or silicone spray to the access panel hinges |
Winterizing
If you do not use the AC in winter:
- Turn off the AC and unplug it (or switch off the breaker)
- Place a breathable cover over the outdoor unit — not airtight plastic, as that causes condensation and corrosion
- Leave the enclosure open for air circulation
- Check in spring that the unit and cover are still in good condition before turning the AC back on
Noise Reduction: Tips for a Quieter Outdoor Unit
Besides visually hiding the unit, you can use a cover to reduce noise as well.
- Rubber anti-vibration pad under the unit — reduces vibrations that resonate through the ground. Costs $17–$28 and makes a noticeable difference
- Sound-absorbing material on the inside — attach acoustic foam (1/2″–3/4″) to the inside of the panels that are not on the exhaust side. Costs $23–$45 for a set. Reduces noise by 3–5 dB
- Do not place the cover against the wall — if the cover touches the house wall, noise resonates through the wall indoors. Keep at least 2 inches between the cover and the wall
- Vibration dampeners on the lines — the copper lines between the indoor and outdoor unit can vibrate. Rubber sleeves around the lines dampen this
Alternative Cover Ideas
Green Cover (Climbing Plants)
Place a wood or metal frame around the unit and let climbing plants grow along it. Suitable plants: ivy, Virginia creeper, or jasmine. Advantage: natural appearance. Disadvantage: you must prune the plants so they do not block the ventilation openings. Always keep the exhaust side clear.
Fence Panel Cover
Use the same fence boards as your existing fence. Build a three-sided enclosure that blends seamlessly into the fence. Advantage: the cover does not stand out. Disadvantage: fence boards are often solid — cut extra ventilation slots or leave the top open.
Gabion Cover (Wire Baskets with Stone)
Place steel wire baskets filled with stones around the unit. Stylish and robust. The gaps between the stones provide sufficient ventilation. Cost: $170 to $450 depending on size and stone type.
Common Mistakes with an AC Unit Cover
1. Cover Too Enclosed — Unit Overheats
The number one mistake. A cover that is too closed blocks airflow. The unit overheats, shuts itself off, and uses more electricity. Ensure at least 40–50% of the surface is open.
2. Blocking the Exhaust Side
The front of the unit blows hot air out with force. If that air cannot escape, the unit sucks its own warm exhaust air back in. Result: the AC no longer cools. Keep the exhaust side open or use angled slats.
3. No Access for Maintenance
The filters of an outdoor unit need to be cleaned at least once a year. Without an access door or removable panel, you have to disassemble the entire cover. Always plan an access point.
4. Using Untreated Wood
Untreated pine rots outdoors within 3–5 years. Use pressure-treated wood, cedar, thermowood, or composite. Or treat the wood with exterior stain or oil.
5. Not Anchoring the Cover
A 3-foot-tall cover catches a fair amount of wind. Without anchoring, it blows over. Secure the cover to the ground (ground anchors), to the wall, or make the base heavy enough.
6. No Anti-Vibration Pad Under the Unit
An outdoor unit vibrates, especially at full capacity. Without a vibration pad, that vibration transfers to the ground, wall, and cover. Result: extra noise. A rubber anti-vibration pad for $17–$28 solves this.
Frequently Asked Questions About AC Unit Covers
How much does it cost to build an AC unit cover yourself?
A wooden cover with slats costs $90 to $225 in materials. A cover with composite or aluminum costs $170 to $340. Ready-made covers cost $170 to $680.
How far should an AC unit cover be from the unit?
At least 6 inches on the sides and back, 12 inches above the unit, and 20 inches at the exhaust side. More space is always better.
Can an AC unit cover reduce noise?
Yes, but to a limited extent. A cover reduces noise by 3–5 dB. Use sound-absorbing material (e.g., acoustic foam) on the inside of the panels for additional dampening. Never block the airflow — that only makes things worse.
Can you place an AC outdoor unit in a fully enclosed box?
No. A fully enclosed box blocks airflow entirely. The unit overheats and shuts down with an error. At least 40–50% of the surface must be open for ventilation.
What is the best wood for an outdoor cover?
Cedar or thermowood offers the best value for outdoor use. Durable, attractive, and low maintenance. Hardwood (ipe) lasts the longest but is more expensive. Composite is the most maintenance-free option.
Building Plans and Guides
Ready to get started with professional building plans and step-by-step guides? Check out the complete building plans package at fredsdiyplans.com — with thousands of plans for every DIY project.
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