The severe winter freeze experienced in the South Central U.S. in mid-February caused widespread plumbing infrastructure problems and was an unexpected benefit that we estimate positively affected consolidated sales by about 3%.
We incrementally spent approximately $2 million of which over half was invested in our smart and connected products.
We plan to increase investment spending for the full year from $13 million to $16 million primarily to support additional growth in productivity projects.
Our proposal impacts approximately 85 employees.
On a net basis we anticipate downsizing by approximately 50 people.
New residential single-family constructions continues to look steady for the year with recent March and year-to-date housing starts positive and multifamily residential starts although lumpy showed some buoyancy recently with March starts up over 30% sequentially.
A recent AGC survey of about 1,500 contractors noted that 77% saw new projects either postponed or canceled in 2020, and 40% are seeing further project cancellations or postponements for the January to June 2021 period.
Second, we recently took part in Project 24 in partnership with the Planet Water Foundation.
We sponsored the installation of an integrated water system and funded a water health and hygiene education program for more than 600 students in a small Vietnamese town.
Since the beginning of our partnership with Planet Water in 2016, we provided approximately 30,000 people in nine countries with safe, clean drinking water.
Sales of $413 million were up 8% on a reported basis and up 4% organically.
As discussed, we had an easier compare in APMEA during the quarter and we estimate sales increase by approximately 3% because of the freeze in the South Central United States.
Foreign exchange, primarily driven by a strong euro, increased the year-over-year sales by roughly $13 million or 3%.
Acquisitions net of divestitures accounted for $4 million of incremental sales year-over-year.
Adjusted operating profit was $60 million, up 24% compared to last year, and adjusted earnings per share were up 31% to $1.24.
Adjusted operating margin of 14.5% was up 190 basis points as volume, price, productivity and cost actions more than offset inflation and incremental investments.
The adjusted effective tax rate was 28% comparable to the first quarter of 2020.
Our free cash flow for the quarter was $32 million as compared to negative $8 million in the first quarter of 2020.
Our goal is to drive free cash flow conversion at 100% or more of net income for the year.
During the quarter, we repurchased approximately 31,000 shares of our common stock for $3.8 million, and as Bob mentioned, announced a double-digit increase in our dividend.
The Americas posted a solid quarter where organic sales up approximately 3%.
This was primarily driven by the tailwind from the freeze in the South Central Region of the U.S., which we estimate provided almost 4% of incremental growth.
Adjusted operating profit increased by 11%, and adjusted operating margin increased by 110 basis points.
Europe delivered a solid quarter with organic sales up approximately 2%, and adjusted operating margin expanded by 350 basis points.
Reported sales also increased by 10% from favorable foreign exchange movements.
Reported sales increased by 76% including 43% of organic growth, 23% from net acquisitions and 10% from favorable foreign exchange movement.
The AVG acquisition provided approximately $3 million of sales, which was in line with our expectations.
Adjusted operating margin increased 15.5 percentage points due to higher third party and intercompany sales volume, and from cost actions and productivity offsetting inflation and investments.
China intercompany activity was up 80% organically benefiting from the U.S. freeze-driven demand.
Further, we anticipate an additional sales benefit of approximately 4% from the continued impact of the freeze in the U.S. and expect restocking actions in the wholesale market.
In total, we estimate consolidated sales may grow organically between 19% and 24%.
In addition, acquired growth should approximate $4 million for the second quarter.
We estimate our adjusted operating margin could range from 13.5% to 14.5% for the second quarter driven by volume and offset partially by incremental investment spending of $4 million and incremental cost of $6 million related to temporary spending reductions in 2020 that we expect will return All-in we estimate the incremental volume to drop through between 25% and 30%.
Corporate cost should approximate $10 million.
We expect interest expense should approximate $2 million in the second quarter or about half of last year's interest charge.
The adjusted effective tax rate should approximate 27%.
We estimate that organically Americas sales may increase in the range of 2% to 7% for 2021, driven by the freeze benefit and the second price increase neither of which was anticipated in our February outlook as well as stronger growth in non-residential repair and replace due to higher GDP expectations.
Sales should increase by about $4 million for the full year from the acquisition of the Detection Group.
For Europe, we are forecasting organic sales to increase between 1% and 5%.
In APMEA, we now expect organic sales to grow from 10% to 15% for the year.
Sales should also increase by approximately $6 million from the AVG acquisition in the first half.
Overall, on a consolidated basis, we anticipate Watts' organic sales to range from up 2% to 7% in 2021.
This is approximately 7% higher than our previous outlook and is primarily driven by the impact of the freeze in the South Central region of the United States, the second inflation driven price increases, and the slightly better end market expectations in our key regions.
We estimate our consolidated adjusted operating margin maybe up 30 to 70 basis points for the year.
This is primarily driven by the drop through from incremental volume, price, restructuring savings of $14 million, and productivity being offset partially by 2020 cost headwinds of $15 million, incremental investments of $16 million, and general cost inflation.
We expect corporate costs will approximate $42 million for the year.
Interest expense should be roughly $7 million for the year.
Our estimated adjusted effective tax rate for 2021 should approximate 27.5%.
Capital spending is expected to be in the $38 million range.
Depreciation and amortization should approximate $46 million for the year.
We expect to continue to drive free cash flow conversion equal to or greater than 100% of net income.
We are now assuming a 1.19 average euro-U.S. dollar FX rate for the full year versus the average rate of EUR1.14 in 2020.
Please recall that for every $0.01 movement up or down in the euro-dollar exchange rate, our European annual sales are impacted by approximately $4 million and our annual earnings per share is impacted by $0.01.
We expect our share count to approximate 34 million for the year.

Summary:
Sales of $413 million were up 8% on a reported basis and up 4% organically.
Adjusted operating profit was $60 million, up 24% compared to last year, and adjusted earnings per share were up 31% to $1.24.