Della / Optima Pro Series
Della Optima Pro 18k R-454B 208/230V Mini-Split
The Optima Pro 18k brings flagship engineering to a 1.5-ton space with near-flat cold-weather output. It rates SEER2 23.5, EER2 12.5, and HSPF2 10, heating 18,000 BTU/h at 47F and holding 17,800 BTU/h at 5F. It is a premium medium-room unit built for cold climates.
Refrigerant generation
R-454B - current-generation refrigerant
Paid link
$1,850 / Fresh price - checked Jul 24, 2026
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Image: Della
- Last sourced
- Jul 24, 2026
SplitAtlas score
8.2 / 10
(23.5 SEER2) among 18k systems
(10.0 HSPF2) among 18k systems
(98.9% heat retained at 5F; -22 F heating floor) among 18k systems
(34 dBA indoor min / 58 dBA outdoor) among 18k systems
(DIY-marketed; 25 ft precharged; 16.4 ft included line set) across the catalogue
(5 verified features) across the catalogue
($1,850 median retail) among 18k systems
(3 manuals; spec sheet) across the catalogue
Key ratings
Buyer review snapshot
Best for / skip if
Best for
- High-efficiency shortlists; SEER2 is 23.5.
Install difficulty
- Electrical: 230V; breaker/fuse 30 A.
- Line set: Flared line connections; precharged 25 ft; included 16.4 ft; max 65 ft.
Alternatives
- Blueridge XS6 Max Efficiency 18,000 BTU R-454B 208/230V (BXS6A18WM0 / BXS6A18UC0)
9.0 score / 18k / SEER2 25.6 / -22 F heating floor / 230V
Exact destination at Alpine Home Air: $2,359.00, checked Jul 24, 2026
- Senville ELITE 18,000 BTU R-454B 208/230V (SENE-18EL-IHH / SENE-18EL-OH)
8.9 score / 18k / SEER2 25.6 / -22 F heating floor / 187-253V
Exact destination at Senville: $1,899.99, checked Jul 24, 2026
- ACiQ Standard 18,000 BTU R-454B 208/230V (ACIQ-18WS-HP230C / ACIQ-18ZS-HP230C)
8.8 score / 18k / SEER2 24 / -13 F heating floor / 230V
Exact destination at HVACDirect: $1,299.99, checked Jul 26, 2026
Availability and price context
- Verified current price: $1,849.96 at Della; availability out_of_stock; checked Jul 24, 2026.
Source date
- Model data sourced
- Jul 24, 2026
- Page reviewed
- Jul 24, 2026
- Source-backed records
- 4
- Newest source retrieved
- Jul 24, 2026
Warranty tiers
Warranty: Lifetime warranty claim on Della product page
Model context
- Structured ratings
- Certification: ENERGY STAR certified. Refrigerant: current low-GWP R-454B. Minimum heating ambient: -22 F.
Strengths
- Retains 17,800 BTU/h at 5F against 18,000 BTU/h at 47F, an almost flat curve into deep cold.
- SEER2 23.5 with HSPF2 10 is efficient in both modes, and it is ENERGY STAR certified.
Weaknesses
- Della's smaller dealer and support network is a step down from established premium brands.
- Professional install is advised, since DIY refrigerant mistakes can void warranty coverage.
Climate suitability
- Minimum heating ambient
- -22 F[1]
- Rated heating at 5F
- 17,800 BTU/h[3]
- Rated heating at 17F
- 15,500 BTU/h[3]
- Rated heating at 47F
- 18,000 BTU/h[3]
Specifications
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- Manufacturer
- Della
- Brand
- Della
- Product line
- Optima Pro Series
- Model number
- 048-TPH-18K2V-23S-IN indoor / 048-TPH-18K2V-23S-OUT outdoor
- Indoor unit model
- 048-TPH-18K2V-23S-IN
- Outdoor unit model
- 048-TPH-18K2V-23S-OUT
- Number of zones
- 1
- Max indoor units
- not published
- Rated cooling capacity
- 18,000 BTU/h[3]
- Rated heating capacity
- 18,000 BTU/h[3]
- Voltage
- 230 V[1]
- MCA
- not published - manufacturer specifies 30 A breaker
- Maximum fuse or breaker size
- 30 A[1]
- Breaker needed
- 30 A[1]
- SEER2
- 23.5 SEER2[3]
- EER2
- 12.5 EER2[3]
- HSPF2 (Region 4)
- 10 HSPF2[3]
- HSPF2 (Region 5)
- not published
- COP
- not published
- COP at 47F
- not published
- COP at 5F
- 1.8 COP[3]
- Minimum outdoor heating temperature
- -22 F[1]
- Minimum outdoor cooling temperature
- not published
- Maximum outdoor temperature
- 131 F[1]
- Indoor noise range
- 34 - 48 dBA[2]
- Outdoor noise rating
- 58 dBA[2]
- Indoor weight
- 30.86 lb[1]
- Outdoor weight
- 93.7 lb[1]
- Refrigerant
- R-454B[3]
- Refrigerant charge
- not published
- Manufacturer coverage
- not published
- Line-set size
- 1/4 in liquid / 1/2 in suction
- Included line-set length
- 16.4 ft[1]
- Maximum line-set length
- 65 ft[2]
- Max line set per indoor
- not published
- Maximum elevation difference
- 49 ft[2]
- Max height between indoor units
- not published
- Wi-Fi support
- supported[1]
- Energy Star status
- ENERGY STAR certified[4]
- AHRI certification number
- 217568639[3]
- Warranty
- Lifetime warranty claim on Della product page
- Install path
- Professional install / DIY-marketed
- Marketing install label
- DIY-marketed
- Retail price
- $1,849.96
- Available retailers
- Della
- Manual links
- AHRI Appendix M1 public detail record 217568639, Optima Pro Series installation and operation guide, Optima Pro 18,000 BTU Della product-page specifications
- Specification sheet
- Optima Pro 18,000 BTU Della product-page specifications
- Last sourced date
- Jul 24, 2026
Retail purchase context
Some retailer links may earn us a commission at no extra cost; paid relationships never change scores or recommendations. Affiliate disclosure
Paid link
$1,850 / Fresh price - checked Jul 24, 2026
Electrical requirements
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- Voltage
- 230 V[1]
- Voltage range
- 208/230V[1]
- Phase
- 1[1]
- Frequency
- not published
- MCA
- not published - manufacturer specifies 30 A breaker
- Breaker needed
- 30 A[1]
- Maximum breaker size
- not published
- Maximum fuse size
- 30 A[1]
- Maximum cooling current
- not published
- Maximum heating current
- not published
- Manufacturer wire notes
- not published
Installation considerations
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- Liquid line
- 1/4 in[1]
- Suction line
- 1/2 in[1]
- Line connection type
- Flared line connections[2]
- Precharged length
- 25 ft[2]
- Included line-set length
- 16.4 ft[1]
- Maximum line-set length
- 65 ft[2]
- Max line set per indoor
- not published
- Max height between indoor units
- not published
- Indoor dimensions
- 43.19 in W x 13.06 in H x 8.75 in D[1]
- Outdoor dimensions
- 36.5 in W x 27.5 in H x 14.94 in D[1]
- Indoor weight
- 30.86 lb[1]
- Outdoor weight
- 93.7 lb[1]
- Drain size
- not published
Related systems and guides
- More Della systems
- Della Optima CloudAir Series 18k 230V
- Della 18k model
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- Della 18k model
- Guide library
- Mini split buying guide
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- Troubleshooting
- Do mini splits work in cold weather?
- Della mini split review: is Della any good?
- The best 18,000 BTU mini splits of 2026
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- Mini split heating capacity in the cold: what your unit actually delivers at 5F
- The mini split defrost cycle, explained
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- What "DIY mini split" actually means
- How to install a mini split (DIY overview)
- Mini split not heating
- Mini split indoor unit freezing up
- Mini split remote not working
- Mini split condensate pump problems
- Mini split Wi-Fi not connecting
- Line sets
- Line-set covers
Frequently asked questions
- Can I install the Della Optima Pro 18,000 BTU R-454B 208/230V (048-TPH-18K2V-23S-IN / 048-TPH-18K2V-23S-OUT) myself, or do I need a pro?
- Della Optima Pro 18,000 BTU R-454B 208/230V (048-TPH-18K2V-23S-IN / 048-TPH-18K2V-23S-OUT) is built for professional installation: the line set must be flared, evacuated, and charged, which requires EPA-certified refrigerant handling. Installing it outside the manufacturer's requirements can void the warranty, so budget for a qualified HVAC installer.
- Will the Della Optima Pro 18,000 BTU R-454B 208/230V (048-TPH-18K2V-23S-IN / 048-TPH-18K2V-23S-OUT) keep heating in a cold winter?
- The manufacturer publishes 17,800 BTU/h of heating output at 5F. Rated heating operation extends down to -22 F. Certified heating efficiency is 10 HSPF2. Match those numbers against your climate's design temperature - in cold regions, output at 5F matters far more than the nameplate capacity measured at 47F.
- What electrical circuit does the Della Optima Pro 18,000 BTU R-454B 208/230V (048-TPH-18K2V-23S-IN / 048-TPH-18K2V-23S-OUT) need?
- Published electrical requirements: 230 V voltage, not published - manufacturer specifies 30 A breaker minimum circuit ampacity, and 30 A maximum breaker or fuse sizing. Confirm the final circuit against the unit nameplate and local code with a licensed electrician.
- How far can the outdoor unit be from the indoor head?
- The published maximum line-set length is 65 ft, and the included line set comes pre-charged for 25 ft. Longer runs than the included set allows typically mean added refrigerant and a pro visit, so measure the planned routing before ordering.
Data sources
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- Della: DELLA Optima Pro Series 18000 BTU 23.5 SEER2 Ultra Hyper Heat Mini-Split AC - Up to 1000 Sq.Ft. official product pageSourced - manufacturer product page
Covers Breaker needed, Maximum fuse size, Phase, Voltage, Voltage range, Included line-set length and more
- Della: Optima Pro Series installation and operation guideSourced - manufacturer technical document
Covers Indoor noise range, Line connection type, Maximum elevation difference, Maximum line-set length, Outdoor noise rating, Precharged length
- AHRI certificate #217568639 - search the AHRI DirectorySourced - AHRI directory
Covers AHRI certification number, Rated cooling capacity, COP at 5F, EER2, Rated heating capacity, HSPF2 (Region 4) and more
- ENERGY STAR: ENERGY STAR exact row check for AHRI 215864147Sourced - Energy Star listing
Covers Energy Star status
Last updated
Jul 24, 2026