By Savvy Mavi — Your Eco-Modern HVAC Guide
When homeowners talk about comfort, they usually talk in BTUs, tons, or SEER ratings. But when I talk about comfort—especially with electric heat strips—I talk about voltage, amperage, and electrical load safety.
Because a 5 kW electric heat kit (like the one inside the Amana J-Series 17,000 BTU PTAC) can be a beautifully efficient heating solution only if the electrical system feeding it is designed correctly.
Sustainable comfort isn’t just about using less power; it’s about using the right power, delivered safely, efficiently, and consistently.
Let’s unpack how smart electrical design transforms 5 kW heat from “energy hog” into “eco-optimized room heating.”
⚡ 1. What a 5 kW Electric Heat Strip Actually Does
A 5 kW heat strip is a built-in electric resistance heater. Unlike a heat pump, which moves heat, heat strips create heat using electricity. Think of it like an oversized, industrial-grade hair dryer coil — but governed by far more safety controls.
🌡️ What You Get From 5 kW
5 kW = 5,000 watts of heat
In BTUs, that’s:
5,000 watts × 3.412 = ~17,060 BTU/h
That means your PTAC’s electric heat kit alone produces as much heat as many small residential furnaces.
But that power draw demands the right voltage, amperage, and wiring.
🧪 2. Why Voltage Matters More Than People Realize
Every electric heater runs on a specific voltage — typically:
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208V (common in multi-unit buildings)
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230/240V (common in homes, hotels, and renovations)
A 5 kW heater behaves very differently depending on which voltage feeds it.
🔍 5 kW at 240V
Amperage = 5,000W ÷ 240V ≈ 20.8 amps
🔍 5 kW at 208V
Amperage = 5,000W ÷ 208V ≈ 24 amps
(Yes — lower voltage = higher amps)
This is HUGE for sustainable design because:
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higher amps = larger breaker
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larger breaker = heavier copper wiring
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heavier wiring = higher install cost
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and potentially greater energy losses
🌿 Savvy’s Rule
Always match the PTAC to the building’s native voltage.
Don’t force 208V equipment onto a 240V circuit or vice versa.
🔗 Verified Reference
Why voltage affects load and amperage (U.S. DOE)
🔥 3. Understanding Amps — The Heartbeat of Electrical Safety
Most homeowners think “amps” are just a number on a breaker. But amps decide:
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wiring thickness
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breaker size
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heat dissipation
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fire safety
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equipment longevity
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and utility cost (due to inefficiency from excessive wire heating)
A 5 kW electric heat strip is no joke — placing it on an undersized circuit can:
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overheat wires inside walls
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cause tripped breakers
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lead to melted insulation
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risk electrical fire
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damage the PTAC, wiring, or thermostat relay
⚠️ Savvy’s Warning
Electric heat is safe only when circuit design is precise.
“Almost enough” amperage is NOT enough.
🧯 4. Breaker Sizing for 5 kW Heat — The 80% Rule
Electrical code requires that continuous loads (3+ hours of operation) not exceed 80% of a circuit’s capacity.
So for a 5 kW heat strip:
🔌 If heater draws 21 amps
21A ÷ 0.8 ≈ 26.25A minimum breaker
→ Install a 30A breaker
🔌 If heater draws 24 amps (208V buildings)
24A ÷ 0.8 = 30A minimum breaker
→ Install a 30A or 35A breaker depending on manufacturer spec
🔧 Wire Gauge
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30A breaker → #10 AWG copper
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35A breaker → #8 AWG copper
🔗 Verified Reference
National Electrical Code continuous load rule summary
🏠 5. Heat Kits & Room Size — Why 5 kW Is Not “One Size Fits All”
A 5 kW heater is powerful — but is it right for your room?
🛏 Small Rooms (100–250 sq ft)
5 kW is usually overkill unless the space is poorly insulated or very cold.
🛋 Medium Rooms (250–450 sq ft)
5 kW is ideal for supplemental heating.
🏢 Large Rooms (450–650 sq ft)
5 kW may be helpful but insufficient on its own; pairing with a heat pump mode is recommended.
Climate Matters
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Northern U.S. → electric heat may run often
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Southern U.S. → electric heat is rare (great for energy savings)
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Humid climates → heat helps with moisture control
🔥🌀 6. Why a 5 kW Heat Kit Pairs Perfectly With PTACs
Heat strips inside PTACs are designed around the airflow and coil geometry of the unit, making them safer and more efficient than standalone heaters.
Benefits of Integrated Heat Strips
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built-in overheat protection
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proper airflow to cool the element
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automatic cutoffs
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multi-stage heat control
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evenly distributed warmth
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reduced energy waste compared to plug-in heaters
Safety Sensors Included in PTACs
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high-limit temperature switches
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fan delay timers (avoid burning smell)
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airflow switches
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safety fuses
Electric heaters outside PTACs rarely include this level of engineered protection.
🧊 7. Heat Pump vs. 5 kW Heat Strip — When Electric Heat Takes Over
A PTAC with heat pump + 5 kW electric heat gives you dual-stage heating.
Heat pump runs:
✔ down to ~40°F (sometimes lower)
✔ extremely efficient
✔ low energy cost
Electric heat kicks in:
✔ for rapid warm-up
✔ when outdoor temps drop too low
✔ when thermostat calls for extra heat
✔ when the room is far below setpoint
The Sustainable Strategy
Use the heat pump as the primary heat source.
Use the 5 kW electric strip as backup or booster.
🔗 Verified Reference
DOE heat pump heating performance:
https://www.energy.gov/energysaver/heat-pump-systems
🧩 8. Designing a Room for a 5 kW Electric Heat Source
This is where sustainable design meets electrical engineering.
🛋 🔥 1. Clear Airflow Around the PTAC
Electric heat strips must be cooled by airflow.
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keep 12–18 inches of space in front
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avoid curtains or drapes blocking intake
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don’t place furniture directly against the PTAC
Poor airflow = overheating = tripped safety switches.
🌡 🔥 2. Know Your Room’s Electrical Load
A 5 kW heater plus:
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TV
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laptop
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lights
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ceiling fan
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chargers
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mini-fridge
…can push a circuit past its limit.
Use a smart plug or energy meter to measure device load.
Verified tool
Calculating appliance load (EnergyStar)
🔌 🔥 3. Use the Correct Receptacle & Plug Type
5 kW PTACs often require:
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NEMA 6-30P plug
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NEMA 6-20P for smaller heaters
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dedicated 208/240V circuit
Never use adapters. Never share circuits.
🧱 🔥 4. Don’t Undersize the Wiring
Thin wire + high amps = wall fire risk.
Always size above load.
🪟 🔥 5. Improve the Room’s Envelope
Better insulation = less electric heat runtime.
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add thermal curtains
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seal windows
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insulate exterior walls
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reduce drafts
Verified guide
Home insulation basics (DOE):
https://www.energy.gov/energysaver/weatherize/insulation
⚙️ 9. How PTACs Regulate Heat Strip Use (Smart Controls)
Modern PTACs—like the Amana J-Series—don’t just blast 5 kW on/off. They use:
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staged heating
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temperature slope logic
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overheat protection
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fan delay control
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freeze sensors
These controls minimize energy waste and maximize comfort.
🧊🔥 10. 5 kW & Humidity — The Missing Link Most People Ignore
Electric heat strips are incredibly effective moisture fighters.
Here’s the secret:
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cold air holds less moisture
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heating expands moisture capacity
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improving humidity balance
Rooms heated by electric heat at low outdoor temperatures often feel:
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drier
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more breathable
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less clammy
This is especially useful in:
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bathrooms next to PTAC-conditioned spaces
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coastal climates
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basements
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rooms with poor ventilation
⚡📏 11. Calculations: What 5 kW Does to Your Energy Bill
Let’s get real about cost.
Example: Heat strip runs 1 hour
5,000 watts = 5 kWh per hour
At $0.12/kWh → $0.60 per hour
If it runs 2 hours a day
$0.60 × 2 = $1.20/day ≈ $36/month
If heat pump handles most of the load
Your electric heat may run only 10–20% of the season.
Savvy Tip
Electric heat should be your supplement, not your core heat source.
🧯 12. Safety Features Every 5 kW Heat Kit Must Have
Your PTAC should include:
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high-temp cutoff switch
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airflow switch
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heating relay
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thermal fuse
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grounded metal housing
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UL/ETL certification
Verified Reference
Federal appliance safety guidelines (CPSC):
https://www.cpsc.gov/Safety-Education/Safety-Guides
If a heat kit is missing these, don’t buy it. Ever.
🛠️ 13. Common Installation Mistakes (Savvy’s Warning List)
These issues are surprisingly common:
❌ Putting a 5 kW PTAC on a shared circuit
→ guarantees breaker trips
❌ Using undersized wire
→ overheating and fire risk
❌ Plugging into the wrong receptacle
→ destroys heater, voids warranty
❌ Poor airflow
→ safety switch shutoff, overheating
❌ Mismatched voltage
→ reduced heat output or equipment failure
🌿 14. Sustainable Heating with 5 kW Heat Strips — Yes, It’s Possible
Electric heat gets a bad reputation because it’s “energy intensive.”
But used correctly:
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with a heat pump
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with insulation
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with efficient voltage use
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with smart cycling
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with good electrical design
…it becomes part of a balanced, sustainable system.
The key is design, not brute force heating.
🎯 15. Final Thoughts — Design the Electricity First, Comfort Second
A 5 kW electric heat kit can be:
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safe
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efficient
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eco-friendly
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powerful
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long-lasting
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stable
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perfect for cold snaps
But only when:
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voltage matches
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amperage is calculated
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breaker size is correct
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wiring is appropriate
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airflow is unobstructed
Good electrical design = good comfort.
Smart wiring = sustainable living.
Sustainable HVAC = the Savvy way.
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In the next topic we will know more about: Green Layouts — How to Design Low-Carbon Comfort With Fewer BTUs and Better Airflow
