- Companies
- Electricians
- Portsmouth
- Thermawatt Ltd
Thermawatt Ltd
- Company number
- 10926325
- Incorporated
- 22 Aug 20179 years trading
- Registered office
- 93 Merrivale Road, Hilsea, Portsmouth, Hampshire, PO2 0TH
- Nature of business
- Electrical installation; Plumbing, heat and air-conditioning installation
Thermawatt Ltd is a 9-year-old private limited company registered in Portsmouth, company number 10926325, one of 148 electrical contractors in Portsmouth. Its next accounts are due at Companies House on 31 December 2027, and the CT600 for the period to 31 March 2027 is due at HMRC on 31 March 2028.
Key dates
Worked out from the year end and filing history on the Companies House register.
Is this your company?
File the accounts to Companies House and the CT600 to HMRC yourself with A.X.E.L Filing. One set of questions, both filings, £49 flat. No accountant, no subscription.
File for Thermawatt LtdOr get a reminder before each deadline
Free. We email you 60, 30, 14, 7 and 1 days before the accounts, CT600 and confirmation statement are due. Unsubscribe in one click.
Finances
From each year's balance sheet filed at Companies House. Small companies do not have to publish turnover or profit, so these are balance sheet figures.
- Net assets up £33K on the year before, to £33K.
- Net assets rose in 1 of 8 year-on-year comparisons on record.
- Current assets of £71K against £49K owed within a year: 1.5 times cover.
- 2 employees on average during the year.
- Balance sheets on record for 9 years, 2018 to 2026.
Net assets by year
| Year end | Net assets | Cash | Current assets | Owed within a year | Employees |
|---|---|---|---|---|---|
| 31 Mar 2026 | £33K | £5,818 | £71K | £49K | 2 |
| 31 Mar 2025 | £1 | £1 | £1 | ||
| 31 Aug 2024 | £1 | £1 | £1 | ||
| 31 Aug 2023 | £1 | £1 | |||
| 31 Aug 2022 | £1 | £1 | |||
| 31 Aug 2021 | £1 | £1 | |||
| 31 Aug 2020 | £1 | £1 | |||
| 31 Aug 2019 | £1 | £1 | |||
| 31 Aug 2018 | £1 | £1 |
Where Thermawatt Ltd is registered
The registered office is in Portsmouth (PO2), in the Portsmouth local authority area, South East. Show PO2 0TH on a map.
Other trade companies in PO2
- South Coast Garden Rooms LtdBuilders
- Novira Automotive LtdMotor traders
- Tony Parrack Fire Protection LtdSpecialist contractors
- Bmgcarpentry LtdJoiners and carpenters
- LLPG Carpentry LtdBuilders
- Xyz Developments LtdProperty developers
- Eco Amend Maintenance Service LtdFinishing trades
- Manila Haulage LtdMechanics and garages
Also registered at this address
1 other company uses the same registered office as Thermawatt Ltd.
- Tech Services (HVAC) LtdElectricians
What happens if Thermawatt Ltd files late
Companies House charges an automatic penalty the day after the deadline, and it rises the longer the accounts are late. These are the dates for this company's accounts due on 31 December 2027.
| Companies House | Accounts delivered | Penalty |
|---|---|---|
| Up to 1 month late | 1 Jan 2028 to 31 Jan 2028 | £150 |
| 1 to 3 months late | 1 Feb 2028 to 31 Mar 2028 | £375 |
| 3 to 6 months late | 1 Apr 2028 to 30 Jun 2028 | £750 |
| More than 6 months late | From 1 Jul 2028 | £1,500 |
Penalties double if the accounts were also late the year before.
| HMRC (CT600) | From | Penalty |
|---|---|---|
| 1 day late | 1 Apr 2028 | £200 |
| 3 months late | 30 Jun 2028 | another £200 |
| 6 months late | 30 Sep 2028 | HMRC estimates the tax and adds 10% of the unpaid tax |
| 12 months late | 31 Mar 2029 | another 10% of any unpaid tax |
For returns filed on or after 1 April 2026. Late three times in a row and the £200 penalties become £1,000 each.
Company details
As held on the Companies House register.
- Company number
- 10926325
- Status
- Active
- Company type
- Private limited company
- Incorporated
- 22 August 2017 (9 years ago)
- Registered office
- 93 Merrivale Road, Hilsea, Portsmouth, Hampshire, PO2 0TH
- Nature of business
- Electrical installation (SIC 43210)
Plumbing, heat and air-conditioning installation (SIC 43220) - Year end
- 31 March (accounting reference date)
- Accounts type
- Total exemption (full)
- Last accounts made up to
- 31 March 2026
- Last confirmation statement
- 2 April 2026
- Previous names
- Regen Investments Limited (until 20 Feb 2025)
Filing notes for electrical contractors
Electrical contracting companies are often a director plus a van and tools. Most fall within the micro-entity rules, so the accounts filed at Companies House are short, and the CT600 carries the tax detail.
Similar companies in Portsmouth
Other active electrical contractors registered in Portsmouth.
- Underground Signs & Graphics Ltd2025
- Urban Installers Ltd2015
- Vanguard Construction Group Ltd2026
- Volt Network Ltd2026
- Volt Tech Services Ltd2024
- Voltkens Ltd2025
- Vuro Ltd2006
- W2 Electrical Limited2026
All electrical contractors in Portsmouth · All trades in Portsmouth · Electricians across the UK
Frequently asked questions
When are Thermawatt Ltd's accounts due?
Thermawatt Ltd's next accounts are due at Companies House by 31 December 2027 (in 444 days), covering the period to 31 March 2027.
When is Thermawatt Ltd's CT600 due?
The CT600 for the period to 31 March 2027 is due at HMRC by 31 March 2028, 12 months after the period end. The corporation tax itself is payable earlier, by 1 January 2028.
Is Thermawatt Ltd still trading?
Thermawatt Ltd is listed as active on the Companies House register as of 1 Oct 2026. Active means it has not been dissolved or entered insolvency; it does not show whether it is currently taking on work.
What does Thermawatt Ltd do?
Thermawatt Ltd is registered under Electrical installation (SIC 43210); Plumbing, heat and air-conditioning installation (SIC 43220).
How old is Thermawatt Ltd?
Thermawatt Ltd was incorporated on 22 August 2017, 9 years ago.
What is the penalty if Thermawatt Ltd files its accounts late?
Companies House charges £150 if the accounts are up to 1 month late, £375 up to 3 months, £750 up to 6 months and £1,500 after that, doubled if the previous year's accounts were also late. HMRC charges £200 for a CT600 filed a day late and another £200 at 3 months.
Official records
View Thermawatt Ltd on Companies House for filed documents, officers and the full history.
Based on the Companies House register (snapshot 1 Oct 2026). Deadlines are worked out from the register and assume a standard accounting period; a change of year end or a short period moves them. This page is general information, not tax or accountancy advice.