Homeowners across the San Francisco Bay Area are upgrading to side-discharge heat pumps — compact, quiet, energy-efficient systems perfect for narrow side yards, patios, and older homes.
At Galaxy Heating & Air Conditioning, we’ve installed hundreds of these units throughout Pleasant Hill, Oakland, Berkeley, Lafayette, Concord, and Walnut Creek, giving us firsthand experience with how each brand performs in real-world Bay Area conditions.
Here’s our 2025 professional comparison of the five most popular side-discharge models we install:
- Carrier 38MURA (Performance™ Series)
- Mitsubishi SUZ & MXZ-SM Series
- American Standard 5HPL5 (16 SEER2)
- Rheem RD18AY (Endeavor Series)
- Lennox EL18KSLV (Elite Series)
🌬 Why Side-Discharge Heat Pumps Are Taking Over the Bay Area
Traditional “top-discharge” systems blow air upward, which can be noisy and require 4+ feet of top clearance.
Side-discharge heat pumps, however, vent air horizontally — making them ideal for small yards, zero-lot-line homes, and dense neighborhoods like those found across Oakland and Berkeley.
Top Advantages:
- Compact, low-profile design — fits beside fences and pathways
- Quieter operation (many units <56 dB)
- Easier service access for technicians
- Cleaner aesthetic for remodels and ADUs
- Qualifies for Bay Area electrification rebates and federal tax credits
⚙️ Quick Technical Comparison
| Model | Efficiency (SEER2) | Noise Level (dB) | Form Factor | Ideal Application |
| Carrier 38MURA | Up to 20 SEER2 | ~56 | Ultra-compact cube | Tight side yards, small lots |
| Mitsubishi SUZ / MXZ-SM | Up to 21 SEER2 | 45–54 | Compact rectangular | Quiet comfort, zoned systems |
| American Standard 5HPL5 | 16 SEER2 | ~55 | Compact side-discharge | Budget-friendly retrofits |
| Rheem RD18AY (Endeavor) | 18 SEER2 | 55–58 | Compact cube | Inland heat, durability |
| Lennox EL18KSLV (Elite) | Up to 18 SEER2 | ~58 | Low-profile premium design | Remodels and high-end homes |
🥇 Carrier 38MURA — Compact Power and Reliability
Series: Performance™
Efficiency: Up to 20 SEER2
Noise Level: ~56 dB
Best For: Tight-lot homes and ADUs
The Carrier 38MURA is Galaxy’s top choice for compact spaces. It’s the perfect balance of quiet operation, inverter technology, and affordability, making it ideal for Oakland, Berkeley, and San Leandro homes with narrow side yards.
Highlights:
- Ultra-compact design fits in 18–24″ gaps
- Variable-speed inverter compressor
- Pairs with existing ducted systems
- Compatible with Carrier, Ecobee, and Nest thermostats
- ENERGY STAR® rated and rebate-eligible
“We installed a 38MURA behind an Oakland duplex with only 22 inches of clearance — it’s quieter than the fridge inside!”
🔇 Mitsubishi SUZ / MXZ-SM Series — Quietest and Most Flexible
Models: SUZ-KA18NAHZ, MXZ-SM36NAM, MXZ-SM48NAM2
Efficiency: Up to 21 SEER2
Noise Level: 45–54 dB
Best For: Older homes, zoning, and ceiling cassette applications
When homeowners ask for the quietest heat pump possible, we recommend Mitsubishi. Their SUZ single-zone and MXZ-SM multi-zone systems deliver unmatched performance and whisper-quiet operation — perfect for bedrooms or patios.
What makes Mitsubishi unique:
- Works with wall units, ceiling cassettes, and slim ducted air handlers
- Ceiling cassettes (MLZ & SLZ series) fit between 16” joists — no reframing
- Inverter-driven compressor for stable, even comfort
- Hyper-Heat technology provides reliable heating down to 5°F
Real Galaxy install:
A 1960s Orinda home with no attic space was upgraded using a Mitsubishi MXZ-SM48NAM2 outdoor unit and four MLZ ceiling cassettes. Every cassette fit perfectly between joists — no major construction required.
Perfect for: Bay Area retrofits, ADUs, and homes prioritizing quiet, zoned comfort.
⚡ American Standard 5HPL5 (16 SEER2) — Efficient and Affordable
Series: Silver 5HPL5
Efficiency: 16 SEER2
Noise Level: ~55 dB
Best For: Homes with existing ductwork
The American Standard 5HPL5 offers reliable inverter-driven comfort in a smaller package. It’s ideal for homeowners upgrading an older ducted system without breaking the bank.
Why Galaxy recommends it:
- True variable-speed operation
- Compact, rectangular outdoor design
- Durable, corrosion-resistant construction
- Works with TEM8 or Platinum Air Handlers
“We installed a 5HPL5 in a 1970s Walnut Creek home — same footprint, but 40% quieter and far more efficient.”
Perfect for: Ducted retrofits in Pleasant Hill, Concord, and Walnut Creek.
🌡 Rheem RD18AY (Endeavor Series) — Tough, Quiet, and Reliable
Series: Rheem Endeavor Line
Efficiency: 18 SEER2
Noise Level: 55–58 dB
Best For: Hot inland climates like Concord, Antioch, or Livermore
The Rheem RD18AY is a powerhouse of durability and consistent comfort. Built with a variable-speed inverter compressor, it’s perfect for Bay Area inland zones where heat, dust, and dry air demand more rugged performance.
Highlights:
- Inverter compressor with sound blanket
- Strong corrosion-resistant cabinet
- Excellent service access and reliability
- Dual-fuel compatibility for hybrid systems
Galaxy tech insight:
The RD18AY is a solid, workhorse system for homeowners who value dependability over flash. It performs extremely well in real-world heat and passes inspections smoothly across Contra Costa County.
🏡 Lennox EL18KSLV (Elite Series) — Modern Aesthetics and Smooth Comfort
Series: Lennox Elite
Efficiency: Up to 18 SEER2
Noise Level: ~58 dB
Best For: Premium remodels and design-conscious homeowners
The Lennox EL18KSLV offers elegant design and precise variable-capacity performance. With a low-profile housing and refined exterior, it’s a favorite among homeowners upgrading both performance and curb appeal.
Why homeowners love it:
- Sleek, modern casing for high-end remodels
- Pairs with Lennox S40 Smart Thermostat
- Variable-capacity inverter maintains ±0.5°F precision
- Excellent match for Lennox ML14XP1 or CBA27UHE air handlers
“We installed the EL18KSLV in a Danville remodel — the homeowner loved that it looked modern and stayed whisper-quiet.”
💸 Installation Costs in 2025 (Bay Area Average)
| Model | Installed Price Range | Best For |
| Carrier 38MURA | $13,000 – $19,000 | Tight-lot ducted homes |
| Mitsubishi SUZ / MXZ-SM | $8,000 – $20,000 | Ductless and zoned installs |
| American Standard 5HPL5 | $12,000 – $18,000 | Ducted retrofits |
| Rheem RD18AY | $12,500 – $18,500 | Inland durability |
| Lennox EL18KSLV | $14,000 – $22,000 | Premium remodels |
Prices vary by project complexity, line-set length, electrical panel readiness, and ductwork condition.
💰 Rebates and Incentives (2025)
Most side-discharge heat pumps qualify for multiple layers of rebates and credits in the Bay Area:
- TECH Clean California: Up to $1,000–$2,000 for qualifying heat pump installations
- Federal Tax Credit (25C): Up to $2,000 for qualifying air-source heat pumps
- Peninsula Clean Energy (PCE): Up to $2,500 for San Mateo County homes
- Silicon Valley Clean Energy (SVCE): Up to $2,000 for Santa Clara County homes
- Bay Area Air District Clean HEET: Up to $13,500 if replacing gas or wood systems
- Galaxy’s Seasonal Promotion: $3,000 OFF any full system installation through October 31, 2025
Stacking these incentives can save homeowners up to $8,000–$12,000 total, depending on eligibility and location.
⚙️ The Galaxy Recommendation Matrix
| Scenario | Our Recommendation |
| Narrow lot or tight fence line | Carrier 38MURA |
| Quietest indoor/outdoor performance | Mitsubishi MXZ-SM / SUZ |
| Best value for ducted retrofits | American Standard 5HPL5 |
| Best for inland durability | Rheem RD18AY |
| Most elegant, modern design | Lennox EL18KSLV |
🌎 Why Galaxy Heating & Air Conditioning Leads in Side-Discharge Installations
We’re not just installers — we’re HVAC design specialists. Galaxy technicians are factory-trained across all major brands, and we custom-design each project based on:
- Space constraints (clearances, fencing, airflow)
- Noise impact (neighbor-friendly placement)
- Electrical load and panel evaluation
- Local rebate optimization
- Long-term service accessibility
Every installation comes with:
- 10-year manufacturer warranty
- 10-year Galaxy workmanship warranty
- Lifetime duct and airflow support options
🎃 Halloween Offer: Save $3,000 OFF any side-discharge HVAC system installation this October!
Call (925) 578-3293 or book online at GalaxyServices.com for your free consultation and rebate analysis.