Buying premium laundry is a multi-thousand-dollar decision. This guide puts dollars first: the LG SIGNATURE WashCombo WM9998HBA (optional 29” SideKick WD405CB) versus LG’s own vented two-unit SIGNATURE stack — a separate washer WM9901HBA and electric dryer DLEX9900B.
Product imagery: LG SIGNATURE WashCombo WM9998HBA (LG USA).
LG’s Consumer Reports track record
Before the money math: LG has multiple Consumer Reports Recommended ratings across its laundry lineup — not one halo model. That matters if you are choosing between an LG combo and an LG vented washer + dryer pair: you are shopping a brand CR has repeatedly rated highly on separate washers and dryers, from mid-price sets to SIGNATURE.
Examples of CR Recommended LG laundry (scores and street prices as shown on Consumer Reports; ratings change over time):
| Pair | Washer | Dryer | Badges | Price each (CR) |
|---|---|---|---|---|
| WM4000HWA + DLEX4000W | 87 | 86 | Both Rec + Green Choice | ~$875–$1,195 |
| SIGNATURE WM9900HSA + DLEX9900S | 87 | 85 | Both Rec | ~$1,795–$1,800 |
| WM8900HBA + DLEX8900B | 86 | 78 | Washer Rec only | ~$1,295–$1,795 |
| WM6500HWA + DLEX6500W | 84 | 83 | Both Rec; dryer Green Choice | ~$1,095–$1,327 |
| WM5500HWA + DLEX5500W | 83 | 81 | Both Rec; dryer Green Choice | ~$1,099–$1,349 |
| WT8600CB + DLEX8600BE | 86 | 83 | Both Rec + Green Choice | ~$1,045–$1,093 |
Consumer Reports Quick Take: LG WM4000HWA (87) and DLEX4000W (86) — both CR Recommended and Green Choice.
Consumer Reports Quick Take: LG SIGNATURE WM9900HSA (87) and DLEX9900S (85) — both CR Recommended.
Consumer Reports Quick Take: LG WM6500HWA (84) and DLEX6500W (83) — both CR Recommended.
Consumer Reports Quick Take: LG WT8600CB (86) and DLEX8600BE (83) — both CR Recommended and Green Choice.
Money takeaway: If you want CR Recommended performance in a classic vented pair, LG gives you several price tiers (roughly $1,750–$3,600 for a matching set at CR’s listed bands). The WashCombo comparison below is about whether one heat-pump unit saves more cash than LG’s own premium two-box SIGNATURE stack — not whether LG can build a good washer. CR scores above are for those specific models; always check current ratings on Consumer Reports before you buy.
The two setups
Option A — One unit: WashCombo WM9998HBA
Ventless all-in-one washer/dryer (Brushed Black Steel):
| Spec | Value |
|---|---|
| Capacity | 5.8 cu. ft. (wash + dry in one drum) |
| Width | 29” |
| Power | 120V / 12A standard plug |
| Dry tech | Dual Inverter Heat Pump (ventless) |
| Energy labels | ENERGY STAR® / Most Efficient; CEF 7.6 |
| Promo (Jul 2026) | $2,399 (list $3,399) |
Money-relevant pros:
- One purchase price instead of washer + dryer
- No dryer vent install
- Heat-pump dry uses less electricity than a conventional vented electric dryer
- Quieter (Direct Drive, TrueBalance®, no vent blower) — easier to fold in the laundry room
- Dehumidifies the load and does not exhaust heated/cooled room air outdoors
LG marketing visual: load once, wash and dry in the same unit.
Option B — Two units: LG SIGNATURE vented washer + electric dryer
Same brand tier, separate machines (LG’s matching SIGNATURE pair for this line):
| Unit | Model | Promo | List |
|---|---|---|---|
| Washer (5.8 cu. ft.) | WM9901HBA | $1,899 | $2,499 |
| Electric dryer (9.0 cu. ft., vented) | DLEX9900B | $1,799 | $2,499 |
| Pair total | ~$3,698 | ~$4,998 |
LG sometimes offers a ~$200 washer+dryer bundle discount on the dryer page — if that applies, pair promo lands near ~$3,498. Even then, the two-unit stack costs about $1,100 more than the WashCombo at current promos.
The vented pair also needs:
- Dryer vent (new install often $200–$800+)
- Typically a 240V dryer circuit (WashCombo uses 120V)
- Two appliance widths (~58” of wall) instead of one 29” footprint
Upfront dollars: combo vs vented pair
| Cost line | WashCombo | Vented pair | You save |
|---|---|---|---|
| Appliances (promo) | $2,399 | ~$3,498–$3,698 | ~$1,100–$1,300 |
| New dryer vent | $0 | $200–$800+ | $200–$800 |
| New 240V circuit | $0 (uses 120V) | $0–$500+ | $0–$500 |
| Day-one total | ~$2,399 | ~$3,700–$5,000+ | ~$1,300–$2,500 |
If you already have a working vent and 240V outlet, the install gap shrinks — but the appliance sticker still favors the WashCombo by roughly $1,100–$1,300 at July 2026 LG promos.
List-price view: combo $3,399 vs pair ~$4,998 → combo is about $1,600 cheaper before promos.
Yearly operating savings (combo vs vented pair)
Heat-pump dry on the WashCombo is the big ongoing lever versus a vented electric dryer. LG’s own dry-cycle testing shows the WM9998 using up to 52% less energy than LG’s conventional-heater combo (WM3998). Versus a full-size vented electric dryer, planning ranges are similar in direction: much less kWh per load, plus no exhaust of conditioned air.
Use ~$0.15/kWh as a national planning rate (scale to your bill).
| Savings line | Yearly savings |
|---|---|
| Dryer electricity | ~$60–$140 |
| HVAC (no vent exhaust) | ~$40–$130 |
| Dehumidification bonus | ~$0–$40 |
| Combined | ~$100–$310 |
Assumptions behind those ranges:
- Dryer electricity: vented electric dry often ~600–1,200 kWh/yr; heat-pump dry commonly cuts that by ~40–60% for similar loads.
- HVAC: vented dryer dumps room air outside every cycle; combo keeps that air indoors.
- Dehumidification: condensing dry may slightly cut whole-home dehumidifier runtime in humid climates.
- Combined: climate, rates, and loads move the needle.
Mid-range worked example: $90/yr less on dry electricity + $60/yr less HVAC ≈ ~$150/year. Over 10 years (no inflation): ~$1,500 in operating savings — on top of the ~$1,100–$1,300 you did not spend on the second machine at purchase.
Planning illustration: heat-pump all-in-one vs a conventional vented washer + dryer pair.
10-year money snapshot (planning)
| Cost line | WashCombo | Vented SIGNATURE pair |
|---|---|---|
| Promo buy-in | $2,399 | ~$3,600 |
| Vent / 240V (if needed) | $0 | ~$400 |
| Extra energy + HVAC over 10 years | — | +$1,000–$3,100 |
| Rough 10-year cash | ~$2,400 | ~$5,000–$6,700 |
Your numbers change with rates and whether vent/electrical work is already done — but in a new laundry room or remodel, the combo’s upfront + operating stack is usually the cheaper SIGNATURE path.
Anchor the rest of the house with the free home energy audit.
Space savings = money you can use
A vented pair needs two 29” footprints (or a stack kit and height). The WashCombo is one 29” width — so the laundry room can hold a folding counter where the dryer would have sat. Load, dry, and fold in the wash room instead of carrying baskets through the house (time and wear on floors/furniture, not just kWh).
Heat-pump dry also dehumidifies and keeps conditioned air inside, which is why the HVAC line shows up in the yearly table above.
Optional SideKick: is another ~$750 worth it?
The LG SIGNATURE SideKick WD405CB is a 1.0 cu. ft. pedestal washer (~$749 promo / $929 list) that sits under the 29” WashCombo.
LG SIGNATURE SideKick WD405CB (product photography from the Best Buy listing).
| Cost line | WashCombo only | WashCombo + SideKick |
|---|---|---|
| Promo total | $2,399 | ~$3,148 |
| Savings vs vented pair (~$3,600) | ~$1,200 | ~$450 |
Buy the SideKick if you run frequent small parallel loads (delicates, gym clothes) and would otherwise run extra full-size cycles — those extra cycles cost water, detergent, and electricity.
Skip it if you mostly run one large load a few times a week — a storage pedestal (LG WDP8B, often ~$300 promo) is cheaper and you keep more of the combo’s upfront advantage versus the vented pair.
SideKick drawer open — small-load capacity under the main unit.
Bottom line: where the $$$ goes
| Question | Planning answer |
|---|---|
| CR Recommended laundry? | Yes — multiple LG washers and dryers across tiers |
| Cheaper to buy? | Combo — about $1,100–$1,300 less at promo |
| Cheaper to run each year? | Combo — about $100–$310/yr less |
| 10-year picture? | Combo often wins by thousands |
| Quiet / fold in laundry room? | Yes — one footprint + quieter heat-pump dry |
| SideKick (~$750)? | Only if parallel small loads pay for themselves |
Promo WashCombo near $2,400 is the money play against LG’s own ~$3,500–$3,700 vented SIGNATURE pair — especially in a remodel without a vent. Run the energy audit for your square footage and state, then price local delivery before you buy.
Sources: LG WM9998HBA WashCombo · LG WM9901HBA washer · LG DLEX9900B electric dryer · LG WD405CB SideKick · Best Buy SideKick listing · Consumer Reports laundry ratings (scores and CR Recommended badges as published for the models listed)
Prices and promotions change; confirm current pricing with the retailer. Energy and HVAC figures are planning ranges, not utility guarantees. Consumer Reports scores and badges are property of Consumer Reports and may change; verify on CR before purchase. Product images are LG / retailer product photography; CR screenshots and energy graphics are illustrative.